To read the full-text of this research, you can request a copy directly from the authors.
Scotland is the largest aquaculture producer in the European Union and utilizes almost all of its fjords for salmon culture. Recent UK policy has encouraged the movement of farm cages away from enclosed sites to areas with strong tidal flow because salmon farms are known to cause organic-enrichment of muddy substrata in areas with low tidal flow. This has resulted in a spate of applications to site cages over coralline algal gravel beds (termed maerl) that are usually strongly tidal and provide habitat for a diverse array of benthic Crustacea. In 2003 we studied the effects of farm waste on benthic crustaceans from a large salmon farm in Shetland that had been situated above a maerl bed since 1991. Annual monitoring reports showed a die-back of living maerl, periods of anoxia and an accumulation of organic material on the seabed within 25 m of the cages. Assessments of crustacean assemblages, quantified using 0.5-mm-sieved replicate (n = 5 per site) core samples, showed significant reductions in biodiversity near the farm. Some scavengers (e.g., the amphipod Socarnes erythrophthalmus) were far more abundant near the cages than at distances >75 m from the cages, but many small crustaceans (e.g., the tanaids Leptognathia breviremis, Typhlotanais microcheles and Psudoparatanais batei; the cumaceans Nannastacus unguiculatus, Cumella pygmaea and Vaunthompsonia cristata; and the amphipod Austrosyrrhoe fimbriatus) were impoverished near the cages. We found that benthic Crustacea were significantly impacted by the salmon farm, despite the presence of strong currents, probably due to the combined effects of organic wastes and the use of toxins to combat parasitic copepods. We recommend that “fallowing”, whereby farm cages are moved between sites to allow benthic recovery, is not carried out at sites where long-lived biogenic habitats such as maerl occur because this will likely increase the area of habitat degradation.
To read the full-text of this research, you can request a copy directly from the authors.
... This species is capable of photosynthesis in relatively low light conditions, although turbidity remains a limiting factor controlling its distribution. In the UK L. corallioides is found at a range of depths up to 30 m, but is found in greater density at depths of 5-10 m, although it has been recorded at depths exceeding 200 m in the Azores where light is able to penetrate [32,33]. ...
... Edwardsia timida is a slender burrowing anemone that can reach 70 mm long and 5 mm in diameter. The tentacles (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32) are arranged in three cycles . The scapulus (column), disc and tentacles are translucent, often orange-pink, yellow or sometimes buff. ...
... Dispersal -due to the predominance of vegetative reproduction, dispersal in this species is thought to be limited . Recruitment -recruitment is thought to be low due to the slow growth and mode of reproduction exhibited by this species [28,32,455] ...
The Marine and Coastal Access Act 2009 created a new type of Marine Protected Area (MPA), called a Marine Conservation Zone (MCZ). MCZs, together with other types of existing MPAs, will deliver the Government’s aim for the formation of an ‘ecologically coherent network of well managed Marine Protected Areas’. Through stakeholder engagement and consultation the Department for Food and Rural Affairs (Defra) has developed seven design principles which are to be applied to the UK network of MPAs;
o Best available evidence
The objective of this study is to address the design principle of viability through the assessment of 37 species and 25 habitats which are likely to be protected by the MPA network (known as features of conservation importance – FOCI). A viable MPA has been defined within the scope of this study as being an area large enough to encompass most naturally occurring ecological processes and the home ranges of the species or groups of species characteristic of habitat communities which are the target for protection. The specific objectives of this viability assessment were to review existing literature to identify
adult home ranges for species of conservation importance and to identify the minimum site area required for each habitat of conservation importance. This review focused on published peer reviewed journal articles but where gaps exist, was supplemented with data and reports produced by Marine Ecological Surveys Ltd as well as other grey literature. As most species in this review are sessile or sedentary the reviews consider several factors other than home range, important to the ecology, and hence viability of species and habitats.
... The same spatial gradient was observed for benthic ecology in Fig. 3 and TOC in Fig. 2. These patterns are similar to those observed in other studies on fish farm impacts (Brown et al., 1987;Hall-Spencer and Bamber, 2007;Mayor et al., 2010) and TOC enrichment from fish farms (Carroll et al., 2003;Kutti et al., 2007;Norði et al., 2011). ...
... Small crustaceans respond negatively to fish farm impact, however, disentangling the attribution of impact to organic enrichment or EmBz effects has previously proven difficult (Telfer et al., 2006;Hall-Spencer and Bamber, 2007). The majority of crustaceans found in this study were amphipods, which are well known to respond to disturbance differently according to lifestyle (Pezy et al., 2018;Poggiale and Dauvin, 2001;De-la-Ossa-Carretero et al., 2012;Wilding et al., 2017). ...
Emamectin benzoate is used as an in-feed treatment for the control of sea lice parasites in all of the main farmed Atlantic salmon (Salmo salar) facilities worldwide (Norway, Chile, Scotland and Canada). Investigations into its effect on non-target benthic fauna resulting from its excretion from farmed fish and uneaten feed have been limited. This paper presents the findings from a study that intended to assess the impact of emamectin benzoate on benthic fauna using a new low detection method for emamectin benzoate. Eight fish farms in the Shetland Isles, Scotland were surveyed, with sediment sampled along transects radiating from the farms analysed for benthic ecology, sediment chemistry and sediment veterinary medicine residues (analysed for emamectin benzoate and teflubenzuron). Canonical Correspondence Analysis (CCA) and Generalised Linear Mixed Modelling (GLMM) were used to assess which environmental parameters observed during the survey had the biggest effect on benthic community composition and abundance, and more specifically crustacean abundance and richness. Emamectin benzoate was found in 97% of samples, demonstrating widespread dispersion in the sediments sampled. The CCA showed that species composition was predominantly ordinated along a gradient of particle size, with a secondary axis dominated by a change in emamectin benzoate and organic carbon enrichment. Peaks in abundance of crustacean species were predicted to be organised along a gradient of emamectin benzoate concentration. The GLMM corroborated this by showing that emamectin benzoate had the strongest negative effect on total crustacean abundance and species richness, though there was some degree of collinearity with organic carbon, that had a smaller effect. Overall, this study shows that, following its use as an in-feed treatment for sea lice, emamectin benzoate residues are more widely distributed in the benthic environment than previously thought, and have a statistically significant effect on benthic ecology at the concentrations observed in this study.
... This study utilised data from impact studies in three distinct habitats which were subject to different anthropogenic pressures. The raw data used to calculate M-AMBI and the IQI have previously been used to characterise the response of benthic invertebrates to: (i) the individual and combined effects of organic matter in intertidal muddy sand sediments O'Gorman et al., 2012); (ii) fin fish aquaculture in maerl in highly tidal coastal waters (Hall-Spencer and Bamber, 2007;Hall-Spencer et al., 2006) and (iii) aggregate dredging in inshore gravel sediments (Cooper et al., 2007(Cooper et al., , 2008a. ...
... The IQI and M-AMBI includes Simpson's index and Shannon-Weiner respectively, which also correlate well with each other, so this result was expected. Although the indices detected changes in infaunal communities along fish farm gradients of organic enrichment, the ES appears to have been overestimated since maerl beds are an unusually diverse habitat even when they are organically enriched (Hall-Spencer and Bamber, 2007). Thus further development of habitat specific reference conditions is necessary to ensure a true reflection of the ecological status of this habitat. ...
... Although not as devastating as dredging, European maerl beds have also been impacted by aquaculture (Hall-Spencer et al. 2006 ;Hall-Spencer and Bamber 2007 ;Peña and Bárbara 2008a ;Peña 2010 ), changes in current patterns associated with construction (Birkett et al. 1998a ;Grall and Hall-Spencer 2003 ), dredge fi sheries (Hall-Spencer 1998 ;Hall-Spencer and Moore 2000 ;Hall-Spencer et al. 2003 ;Hauton et al. 2003 ;Kamenos et al. 2003 ), as well as increased sedimentation and eutrophication (Hily et al. 1992 ;Grall and Glemarec 1997 ). There is also a growing realisation that these habitats may be especially vulnerable to ocean acidifi cation since the high Mg-calcite skeletons of coralline algae dissolve easily as CO 2 levels rise (Nelson 2009 ;Büdenbender et al. 2011 ;Porzio et al. 2011 ;Diaz-Pulido et al. 2012 ;Noisette et al. 2013 , see Chapter by Martin and Hall-Spencer). ...
... Many of these studies confi rmed the negative effect of ocean acidifi cation, rise of temperature and burial on the physiology of rhodolith-forming species, suggesting that a combination of physical stressors can affect coralline species and the fl ora and fauna assemblages associated with them. Also, the negative effects on the rhodolith bed structure and disturbance and loss of diversity of the associated fl ora and fauna has been documented, mostly due to anthropogenic activities such as bivalve fi shing and aquaculture (BIOMAERL Team 1999 ; Barberá et al. 2003 ;Hall-Spencer et al. 2003, 2006Hall-Spencer and Bamber 2007 ;Peña and Bárbara 2008a ;Peña 2010 ). Apart from the decrease in the cover and thickness of the living maerl layer, a decrease in maerl size was observed in Galician beds impacted by mussel aquaculture (Peña 2010 ). ...
Beds of coralline algal sediment form ecologically and economically important habitats in the North Atlantic. These habitats can occur from the intertidal down to 60 m depth, and they are locally abundant in several countries. Thirteen species of coralline algae form rhodoliths or maerl in this region; Lithothamnion corallioides, L. glaciale, L. tophiforme and Phymatolithon calcareum are the most widely recorded. The structure and biodiversity of these habitats is destroyed by dredging and can be degraded by towed demersal fishing gear and by mussel and salmon farming. Legislation has been passed in the European Union (EU) to protect P. calcareum and L. corallioides which should be extended to include the other maerl species from the region. Outside the EU there is a lack of baseline information concerning the importance of these habitats: a fuller understanding of their role may lead to protection in Scandinavia, Iceland and the Atlantic coasts of Canada and the United States. The design of such protected areas would need to consider the ongoing effects of invasive species, ocean warming and acidification.
... Maërl beds have undergone well-documented declines in condition and are being removed for commercial use in Regions I, II, III and IV whereas Region V has no reported impacts. Scallop dredging, construction projects and fish-farming currently impact certain maërl beds in the UK (Hall-Spencer & Moore, 2000a,b;Hall-Spencer et al., 2006;Camplin, 2007;Hall-Spencer & Bamber, 2007) but commercial extraction of this habitat was discontinued in 2005 (Hall-Spencer, 2005). Irish maërl beds are generally considered to be in good condition but some are deteriorating due to commercial extraction, mariculture, demersal fishing and the localized effects of boat mooring chains (Vize, 2005). ...
... Extraction is ongoing in Iceland, Ireland and France and has major effects on the species present due to the direct effect of habitat removal and impacts from increased sediment loads which smother surrounding communities (Hall-Spencer, 1998;De Grave & Whittaker, 1999;Barbera et al., 2003). Maërl beds are also threatened by the use of demersal fishing gear, most notably scallop dredges and suction dredges in UK and Irish waters (Hall-Spencer & Moore, 2000a,b;Hauton et al., 2003), and by mariculture activities that pollute the seabed in Spain, France, Ireland, the UK and probably Norway (Barberá et al., 2003;Wilson et al. 2004;Hall-Spencer et al., 2006;Peña et al., 2006;Hall-Spencer & Bamber, 2007). Coastal construction and sewage may also impact maërl beds through increased sediment loads and/or the stimulation of excessive growth of ephemeral species of macroalgae (Birkett et al., 1998;De Grave et al., 2000;. ...
... Furthermore, there have been studies tackling the effects of anthropogenic impacts on the rhodoliths beds (mainly in Europe, e.g. Barbera et al., 2003;Hall-Spencer and Bamber, 2007;Riul et al., 2008;Hall-Spencer et al., 2010), showing that these habitats are extremely vulnerable to direct human action and even to more indirect ones, such as global warming and ocean acidification (Horta et al., 2016;Martin and Hall-Spencer, 2017;Riosmena-Rodríguez et al., 2017;Sordo et al., 2018Sordo et al., , 2019Koerich et al., 2021). Still, few have addressed the effects of organic enrichment (Hall-Spencer et al., 2006;Horta et al., 2016) or tourism pressures (but see Costa et al., 2019), which are prone to occur in some tropical regions, such as Brazil, with poor sewage waste management (Barletta et al., 2019;Brauko et al., 2020). ...
This study characterized rhodolith beds and the structure and function of their invertebrate communities in three tropical beaches subjected to different environmental impacts. The highest rhodolith density and invertebrate diversity and density were found on a beach with coarser sands (interpreted as indicative of higher hydrodynamics) and the high availability of calcium carbonate in nearby locations. On the opposite, higher rhodolith mortality, lower invertebrate diversity and density were recorded in the beach with high thermotolerant coliforms concentrations and finer sands. The functional composition was similar in the less polluted beaches, despite differences in sediment composition. In these beaches, polychaetes and echinoderms dominated, being primarily biodiffusors, with slow free movement and predators. These traits appeared advantageous due to food and structural protection provided by rhodoliths while providing oxygenation and remobilization of sediment by resident biodiffusers fauna. The most polluted beach was marked by lower densities of those taxa and traits, with suspension feeders’ bivalve dominance, with limited movement, associated with higher suspended material, common in organic polluted environments.
... Rhodolith beds are highly productive habitats (Martin et al. 2005) and are one of the main biogenic deposits of CaCO 3 on the planet (Steller and Cáceres-Martínez 2009;Johnson et al. 2012;van der Heijden and Kamenos 2015;Hernandez-Kantun et al. 2017;Schoenrock et al. 2018), with a potential role in climate regulation (Martin et al. 2007; Amado- Filho et al. 2012). Still, these habitats are vulnerable to numerous human-induced impacts, such as dredging (De Grave and Whitaker 1999;Foster 2001; Barbera et al. 2003;Grall and Hall-Spencer 2003), aquaculture (Hall-Spencer et al. 2006;Hall-Spencer and Bamber 2007;Peña and Bárbara 2008;Sanz-Lázaro et al. 2011), changes in hydrodynamic patterns associated with coastal development (Birkett et al. 1998;Grall and Hall-Spencer 2003), fisheries (Hall-Spencer 2000;Hall-Spencer et al. 2003;Hauton et al. 2003;Bernard et al. 2019), increased sedimentation and eutrophication from diverse sources (BIOMAERL team 1999; Barbera et al. 2003;Wilson et al. 2004), the spread of invasive species Peña et al. 2014), and also ocean acidification (Büdenbender et al. 2011;Noisette et al. 2013;Sordo et al. 2018Sordo et al. , 2019Sordo et al. , 2020. ...
Despite its worldwide distribution in sedimentary infralittoral and circalittoral bottoms,
rhodolith beds have been the subject of fewer studies than other nearshore communities, like kelp forests and coral reefs. This is also the case in Madeira archipelago (Eastern Atlantic), where until recently our knowledge on rhodolith beds was limited to a few
references to its occurrence and species composition. In the course of an ongoing habitat-mapping project developed in Madeira, observations revealed that rhodolith beds are
more common and extensive than previously supposed. The habitat maps for these beds
in Madeira archipelago here presented are the frst ever produced for the region. They
reveal a total of 46 rhodolith beds at eleven diferent locations spread across three islands
(Madeira, Desertas and Porto Santo), with areas ranging from 776 to 101,081 m²
and at depths between 12 and 35 m. Author’s observations, as well as the results suggest that more rhodolith beds are likely to exist in the archipelago, particularly at greater depths
and unexplored locations. The application of molecular systematic tools for the identifcation of rhodolith-forming species revealed the occurrence of four species belonging to the genera Lithothamnion and Phymatolithon. This latter genus is represented by a single species which is commonly found in rhodolith beds of the archipelago. Genetically, our results show similarities both with the rhodolith communities from the Canary islands and the Algarve (south of Portugal) and highlight the singularities of the archipelago’s marine flora. The new array of data here presented is deemed essential for an efective management and conservation of these important and sensitive habitats.
... Additionally, high flow sites have been associated with relatively unique communities that can take longer to recover with cessation of farming compared with more conventional low flow sites (e.g. Hall-Spencer and Bamber, 2007). Therefore, from an environmental management perspective, the relative merits of the different management strategies must invariably be assessed on a case by case basis. ...
... The infaunal community of this area is comparatively diverse, with high species richness, and, except towards the inner harbour, dominated by peracarid crustaceans, as is typical of maerl-associated communities (e.g. Hall-Spencer & Bamber, 2007). ...
... Species of Socarnes are widely distributed and are found in shallow to deep water, from the Arctic to the tropical South Pacific including temperate regions (Mediterranean and East Asia). Ecologically, they are well known scavengers (Lowry and Stoddart 1994;Hall-Spencer and Bamber 2007). The genus is relatively small, being comprised of 10 species. ...
A new species of lysianassid amphipod belonging to the genus Socarnes Boeck was collected from Korean coastal waters. This is the first record of the genus Socarnes from Korea. The new species is fully illustrated and extensively compared with related species. A key to Socarnes speciesis provided.
... Di¡erent BAP habitats/species will demonstrate different sensitivities to the presence of a salmon farm. Those species typically found in higher energy environments, particularly ¢lter feeders, are likely to be highly sensitive to clogging e¡ect of particulate material derived from salmon farms (Hughes, Cook & Sayer 2005) and include maerl and associated fauna (Hall-spencer, White, Gillespie, Gillham & Foggo 2006;Hall-Spencer & Bamber 2007). Beds of M modiolus (and associated fauna) may also be sensitive to the interstitial hypoxia associated with the accumulation of salmon farm detritus. ...
Abstract Man's impact on biodiversity depends on both the type of intervention and the nature of the receiving environment. In the context of salmon farming, environmental impacts occur largely through the flux of farm-derived organic detritus to the seabed. In order to assess these potential impacts this research aimed (a) to identify sensitive benthic habitats, particularly those categorized as Biodiversity Action Plan (BAP) habitats, in relation to salmon farming; (b) to identify and classify the nature of the benthic habitats that occur around Scottish salmon farms and assess the overlap between sensitive habitats and salmon farms; and (c) to conduct a pilot investigation into the abundance of the sea pen Pennatula phosphorea around a single salmon farm. The benthic habitat occurring underneath Scottish salmon farms consisted, predominantly, of muds (58%) and shelly sands (27%) with the bed-type rock, also frequently occurring in close proximity (though not directly underneath) salmon farms. Most farms were located in water between 20 and 50 m deep. These findings are commensurate with the Scottish salmon-farming industry being located in relatively sheltered sea lochs, in close proximity to the shore. Salmon farming was considered, on the basis of spatial overlap and habitat sensitivity, to pose a high risk to maerl and beds of Modiolus modiolus and, on the basis of a lack of information, sheltered muddy gravels and the megafauna associated with the mud in deep water BAP. Sea pen abundance was highly variable but was reduced in close proximity to the salmon farm. While abundance increased to a maximum of 10 per transect at intermediate distances, at the farm peripheries numerous transects were found, again, to contain no sea pens. This may have been as a consequence of the protection offered by the physical presence of the salmon cages against trawling that occurs in the vicinity of the farm.
... However, the practice of fallowing requires that there be sufficient area for stock to be rotated, which in turn implies that a larger area of seabed may be impacted. This can be an important constraint, for example in areas where farms are situated close to habitats containing long-lived organisms that are more sensitive to enrichment (Hall-Spencer and Bamber, 2007). Understanding the effectiveness and sustainability of fallowing is of course particularly pertinent where multiple cycles are employed and there may be potential for cumulative impact (Macleod et al., 2007), or where the system resilience may be compromised (Borja et al., 2010). ...
This paper describes a two-year study of spatial and temporal patterns and processes in the benthos in response to the removal of salmon cages from a sheltered coastal embayment, coupled with the simultaneous reintroduction of cages at an adjacent location. Significant recovery was evident at the fallowed site in the first six months; however, the macrofaunal assemblage remained impacted at the conclusion of the study. By comparison, the reintroduction of a fully operational farm overwhelmed the macrobenthic community within three months, with anoxic and near-azoic conditions developing. Both removal and reintroduction of the farms triggered alternating oscillations of geochemical and biological variables, which were attributed to effects on sediment chemistry from organic loading, ‘boom and bust’ cycles of opportunistic taxa in response to food supply, and the associated variations in metabolic potential. The study also revealed interesting spatial dynamics in the benthos and some useful indicators of different stages of recovery and re-impact. It is concluded that farm reintroductions should aim to gradually increase production; allowing time for the benthos to adapt to the additional organic flux, and be maintained at a level that avoids macrofaunal collapse. The sediments ability to cope with organic inputs from fish farming, and hence the duration of the recovery period, is contingent on the organic load in each farming cycle and the extent to which the sediment community is allowed to recover. Understanding the influence of each of these on sediment processes is important for sustainable long-term management of farming operations.
... Out of Mediterranean areas, in a salmon fish farm off the west coast of Scotland, clear signs of benthic community alteration were found close to the cages and a station 50 m from the cages showed less but still evident impact (Pereira et al., 2004). A sharp decrease in biodiversity and maerl bed modifications along a gradient from the cages to a distance of 100 m were reported in another salmon farm in Scotland (Hall-Spencer et al., 2006;Hall-Spencer and Bamber, 2007). In five salmon farms in Norway, severe disturbance to benthic fauna was found close to cages and absence of benthic impact at a distance of 50 m (Carroll et al., 2003). ...
The effects of solid organic wastes from a marine fish farm on sediment was tested using macrobenthic fauna as biological indicators. Impact on benthic fauna was evaluated in the vicinity of a fish farm in the Tyrrhenian Sea (Western Mediterranean) between July 2001 and October 2002. Changes in benthic community structure were investigated using multivariate, distributional and univariate analyses (diversity indices, AMBI and M-AMBI). The results showed sharp disturbance of assemblages under the cages and no effects in the area more than 25 m from the cages. Sediment alterations were related to an increase in farmed biomass and its wastes, as well as to low current speed that allowed accumulation of organic matter on the sea floor. It was possible to follow the ecological succession from slightly altered assemblages to heavily polluted ones in the very short period of a single fish fattening cycle (15 months).
... Mangion et al. (2014) found changes in Capitellidae and Paraonidae, so the relative importance of these families could change depending on biogeography, seasonal or local environmental variations such as in granulometry. Moreover, a decrease in abundance and diversity of crustaceans has been reported near Mediterranean sea bream and sea bass farms (La Rosa et al., 2001;Fernandez-Gonzalez & Sanchez-Jerez, 2011), as well as Scottish salmon farms (Hall-Spencer & Bamber, 2007). However, in the present study some amphipod families showed a positive response to the moderate impact from the fish farm, substantially increasing their abundances under these conditions. ...
The rapidly expanding Atlantic bluefin tuna fattening industry is characterized by high stock densities and a high input food biomass in the form of whole bait seafood. The environmental impact of this activity must be effectively monitored within a proper sustainable development framework, to address concerns about the potential adverse effects. However, evaluation of monitoring tools for tuna farming has received less attention than other activities. Based on the principles of key taxa (Pocklington and Wells, 1992), we tested the potential use of changes in benthic macroinvertebrate assemblages, polychaetes and amphipods for this purpose. Applying a non-parametric multivariate approach for monitoring the impact of this aquaculture activity on the benthic habitat, we checked for correlations with the physicochemical environmental variables of the sediment. A hierarchical spatial design was followed, using multiple controls. Amphipods and polychaetes showed dissimilarities between impacted and control locations, with significant differences for total assemblage structure at a taxonomic level of families. Total nitrogen (TN) and total sulfur (TS) concentrations were the variables best associated with these changes for amphipods, and d 13C and total phosphorus (TP) were the best for polychaetes. However, total free sulfides (TFS) and TP were the chemical variables that best indicated the effects on sediment. Using this approach, surrogating the whole benthic assemblage to a single taxocene, our data suggest that monitoring tuna farming impact by comparing the changes in amphipod and polychaete assemblages at family level could be an optimal procedure with an excellent cost/benefit ratio.
... Corophiidae showed a low abundance at the impacted plot. Previous workers recorded a decrease in abundance of crustaceans (Fernandez-Gonzalez & Sanchez-Jerez, 2011;La Rosa, Mirto, Mazzola & Danovaro, 2001) near Mediterranean sea bream/sea bass fish farms, and in the diversity of crustaceans in the vicinity of a Scottish salmon farm (HallSpencer & Bamber, 2007). The polychaete/amphipod ratio (BOPA) is a measure of the relative abundance of non-sensitive opportunistic species to sensitive species in organically enriched sediment (Dauvin & Ruellet, 2007;Gomez-Gesteira & Dauvin, 2000). ...
The overall impact of tuna farming on soft-bottom habitat was assessed at three tuna farms over a period of 3 years, using benthic macroinvertebrates as indicators. Polychaetes and amphipods served as better indicators of the impact of tuna farming compared with molluscs and decapods. Lower number and Shannon–Wiener diversity of polychaete and amphipod taxa were recorded over time at the impacted plots compared with the control plots, while the polychaete/amphipod index indicated that the Ecological Quality Status at the impacted plots changed from “Poor”/”Moderate” to “Good” during the study period. Results of the multivariate analyses indicated significantly higher dispersion of samples of the polychaete and amphipod assemblages over time at the impacted plots compared with the control plots, indicative of stressed assemblages. Differences in the macroinvertebrate assemblages between impacted and control plots were consistent across faunal groups except for molluscs, which showed no response. Results must be interpreted with caution due to the high spatiotemporal variation in the influence of tuna farming on the macroinvertebrate assemblages, which highlights the importance of including multiple impacted and reference areas, as well as replicate sampling times, in assessing the environmental impact of tuna farms.
... For example, large-capacity farms situated along the Norwegian coastline can discharge as much as 10 tons of fish faeces per day to the marine environment ; the majority of which is observed to be strongly concentrated in the first hundreds of meters around the farm. POM contains large amounts of carbon, nitrogen and phosphorus, making it an important precursor for organic enrichment of the benthic habitats, carrying the potential to generate anoxic or even azoic conditions in the close proximity to the farm (Brooks et al., 2002;Hall-Spencer and Bamber, 2007;Keeley et al., 2012). Moreover, this type of waste can be associated with a suite of potentially toxic contaminants, principally copper and zinc (Brooks and Mahnken, 2003;Dean et al., 2007;Macleod et al., 2014), but also historically, antibiotics and other feed-administered therapeutants (Burridge et al., 2010) which can pose a threat to marine life should they accumulate and become sufficiently concentrated. ...
An accurate representation of the particle organic matter (POM) footprint is necessary in order to effectively predict impacts upon benthic communities and the risk of excessive organic enrichment beneath aquaculture sea-cages. Consequently, bottom-related processes such as particle resuspension must be adequately parametrized and evaluated in the available numerical models. We implemented two approaches to model POM resuspension in a Lagrangian particle tracking model and compared their influence on footprint extension and gradients of depositional flux against a no-resuspension scenario. We performed simulations in both exposed and protected aquaculture locations, and at different stages of the Atlantic Salmon (Salmo salar) production cycle in Norway. Our results indicate that the use of sediment-dependent thresholds for resuspension has the potential to regulate the high levels of erosion produced when selecting a low critical value in constant-threshold approaches , particularly in dynamic environments with mixed sediment types.
... Current environmental monitoring of benthic communities around salmon farms commonly focuses on characterising community measures such as biodiversity, abundance, and species richness (Hall-Spencer and Bamber, 2007, Fletcher et al., 2019, McGrath et al., 2019a. Obtaining accurate estimates of these measures requires considerable time and taxonomic skill. ...
Local differences in trophic structure and composition of organic matter subsidies can influence the capacity of soft sediment communities to assimilate recycled organic matter from processes such as salmon farm enrichment. The present study combines biochemical analysis with biomass density information on soft sediment taxa collected within the depositional footprint of salmon farms and at reference sites in the Marlborough Sounds, New Zealand. Distinct biochemical signatures confirmed that the flux of organic matter from salmon farms was an important subsidy for soft sediment communities. Isotopic modelling demonstrated that the proportion of biomass supported by farm-derived organic matter did not change in a consistent pattern along the 300 m gradient from each farm site, whereas the average trophic level of communities decreased with increasing proximity to farms. High variability in both the total biomass and the distribution of biomass across trophic levels occurred among sites downstream of farms and among individual farms. Consequently, estimates of basal organic matter assimilation per unit area by communities differed by several orders of magnitude among sites. Total organic matter assimilation tended to decrease with increasing proximity to farms due to a shift towards a more detrital based community. Differences in basal organic matter assimilation among farms did not appear to be directly related to local flow regime, but instead was closely linked to differences in the soft sediment community composition likely influenced by an array of anthropogenic and environmental factors. The results presented here highlight the importance of considering local variability in basal organic matter source pools, and the potential for synergistic and cumulative effects to drive changes in food web trophodynamics when assessing the impacts of aquaculture on soft sediment communities.
Due to its huge extension and inaccessibility Chilean Patagonia for the longest time has been seen as a pristine region with never ending marine resources. But as a byproduct of the inaccessibility its ecosystems are still poorly known. During the last two decades, the aquaculture industry brought an unparalleled economic development to the area and the number of small-scale fishermen who go for pelagic and demersal fish and shellfish multiplied. Since 2003, we have been studying the benthic biodiversity of the Comau Fjord, Northern Patagonia. We have compared benthic photos that show large, long-living species down to 40 m depth on a key study site, which were taken in 2003 and again in 2013. Additionally we compared the decapod fauna which was inventoried in 2005/2006 and again in 2011. The analysis of photographs taken during the last ten years of taxonomic studies demonstrated an important decline in abundance in megabenthic species, throughout several taxa.
Seven species of Thyasiridae are reported from the Oman Margin of the Arabian Sea at depths between 688 m and 3356m. Hypoxic conditions exist at depths between 400 and 1200 m and three species are restricted to this zone and to the Arabian Sea. Leptaxinus indusarium has also been recorded from the Indus Fan and Channelaxinus investigators from off Sri Lanka. A new species Thyasira anassa sp. nov. is described from the hypoxic zone. Another four species are recorded from the abyssal zone where oxygen levels are typical for the deep ocean. Here another new species is described, Parathyasira bamberi sp. nov. but the other species could not be conclusively identified because of close affinity with populations from other oceans. Deep water Atlantic species Axinulus croulinensis and Mendicula ferruginosa are apparently present in the abyssal Indian Ocean while another thyasirid shell is very close to Channelaxinus excavatus from the Eastern Pacific and C. perplicata from the Atlantic. Accompanying these abyssal thyasirids were other bivalve species, Deminucula atacellana, Limopsis pelagica and Bentharca asperula that cannot be distinguished by morphology from their Atlantic populations. It is concluded that using morphology alone that the abyssal species may well be cosmopolitan
This special issue honours the life and work of Roger Bamber, who made an outstanding contribution to the field of marine biology and taxonomy. Roger died in February 2015 at the age of 65, from complications arising from severe motor neuron disease (Amyotrophic lateral sclerosis). This was a tragic loss for his former wife Jane, family and all who knew him. The editors chose Zootaxa for this special issue since Roger had considerable involvement with the journal over many years as subject editor for the Pycnogonida, Tanaidacea and Cumacea. We are grateful to Zhi-Qiang Zhang, Editor-in-Chief of Zootaxa, for making this possible. This issue, which attracted a total of 20 papers from 44 authors, is testimony to Roger's influence and popularity both as a scientist and the personal friendships he made throughout his distinguished career. The contributing authors are based in Australia,
Effects of sea bass and sea bream farming (Western Mediterranean Sea) on peracarid crustacean assemblages. Benthic soft–bottom assemblages are good indicators of environmental disturbance, such as coastal aquaculture, considering their rapid response in terms of diversity and abundance. The aim of this study was to evaluate the response of peracarid assemblages to the release of waste from coastal farming as these organisms play an important ecological role. Abundance and species richness did not show significant differences between farm and control localities but did show a high spatial variability at the two studied scales. Non–metric multi–dimensional scaling (MDS) analysis showed a separation between farms and controls, indicating that peracarid assemblages are modified as a result of aquaculture activities, and some species such as Ampelisca spp. showed statistical differences. Peracarids, at both species and community level, may therefore be applied as helpful indicators to assess benthic effects of coastal farming.
This is a comprehensive list of all answers collected from the CNA-TG survey which were allowed in free-text form, i.e. not pre-coded as multiple choice, tick-boxes or radio buttons. These have been arranged by question, then alphabetically. All six language-specific surveys have been merged together. The small number and letter code at the right of each answer corresponds to the respondent’s automatic ID and language of the original survey and allows cross-referencing.
A 5-factor design survey was carried out to examine the spatial distribution at different
scales of amphipod assemblages and sedimentary variables in soft bottoms adjacent to coastal
aquaculture installations. Natural variability of sediment variables showed the highest values at
the scales of sites (10s of meters) and locality (1 to 10 km), while the greatest component of variation
of amphipod assemblages occurred among replicates (on the scale of meters). Regarding the
influence of coastal aquaculture, the highest variability of the environmental variables was
observed among the different fish farms. On sandy localities, the influence gradient of coastal
aquaculture was determined by total free sulphides, whilst, in muddy localities, the main variable
was δ15N. This study has important consequences for the establishment of a clear and effective
methodology for studying and monitoring the impact of fish farming, highlighting the complicated
establishment of a widespread pattern of effects by coastal aquaculture. The necessity to apply a
high replication effort at several spatial scales, especially at the scales of meters and 10s of meters,
to increase the precision of estimates of assemblage composition should be taken into consideration.
In the context of the limited information on the ecology of port communities, the present work aims at assessing the small-scale spatial variability of zoobenthos inhabiting hard and soft substrata, in a Mediterranean port with high levels of commercial shipment. Samples were collected in summer from three stations and four depth levels, using core and quadrate samplers. A total of 34,578 individuals were collected, identified to 118 animal species. Soft substratum communities were impoverished and their structure varied spatially according to sediment composition. At a functional level deposit feeders dominated; their abundance decreased at the silty sites. Biotic indices were found inadequate for the assessment of ecological quality, due to the very low abundance of the fauna. Fouling communities varied spatially in vertical scales; diversity indices and the abundance of Bivalvia varied also in horizontal scales. Suspension and deposit feeders dominated showing a decreasing trend with depth. Two animal-dominated communities, serpulid blocks in the lower midlittoral zone and mussel beds in the sublittoral, substituted an algal-dominated community, which has been previously recorded from the same port quays. This substitution may be due to the intensive mussel farming in the nearby area contributing to the rapid expansion of mussels and of their serpulid biofoulers. Despite the existence of biogenic substrata, which enhance habitat complexity, the diversity of the associated fauna decreased and most species were tolerant to organic pollution. Recursive biomonitoring seems necessary to assess the ecological status of communities and to develop integrated management plans for temperate ports.
Rhodolith beds are the dominant submerged calcifying aquatic vegetation in some coastal marine environments worldwide but few quantitative data are available regarding their physiology. In the Gulf of California (Mexico), Lithophyllum margaritae (Rhodophyta, Corallinaceae) is the most abundant nongeniculate, rhodolith-forming coralline species. Over their gulf-wide distribution, rhodoliths are exposed to a wide range of seasonal temperatures (~8-32ºC). The effect of changes in temperature on the photosynthetic and calcification rates of this species is unknown. We therefore evaluated the effect of temperature (10-30ºC) on the photosynthetic and calcification rates of L. margaritae rhodoliths in the lab and examined the effect of seasonal changes in temperature on growth rates in the field. Photosynthetic rates were evaluated polarographically and calcification rates were evaluated in the lab using both the buoyant weight technique and total alkalinity method, and in the field through alizarin staining. To the best of our knowledge, this is the first time that these three methods are used simultaneously to evaluate growth rates in coralline algae. Photosynthetic, calcification and growth rates showed wide fluctuations as a result of laboratory or field temperature. Photosynthetic (Pmax) and respiratory rates both increased five-fold as incubation temperature increased to 25- 30ºC. Similarly, calcification rates in the lab and growth rates in the field increased with higher temperatures. The lab data suggest that rhodolith growth is seasonally regulated by seawater temperature. The buoyant weight and total alkalinity techniques for determining calcification rate were comparable at low temperatures, but variability increased with temperature and this will be examined in further studies. Field growth rates, presented as apical tip extension, were significantly higher in summer (5.02 ± 1.16 mm yr-1) than in winter (0.83 ± 0.16 mm yr-1), supporting the lab results. The strong effects of temperature on photosynthetic, calcification and growth rates of Lithophyllum margaritae in the Gulf of California suggest that changes in sea surface temperature directly regulate bed production
We quantitatively assessed the relative contribution of the rhodolith form of Lithothamnion muelleri, a likely foundation species, to macroorganism diversity in a community also inhabited by the large fucalean Sargassum horridum at a site near Cabo Los Machos at the mouth of Bahía Concepción, Baja California Sur, Mexico. The composition and abundance of seaweeds, epibenthic invertebrates, and fish were estimated in March and October 2003, and invertebrates within rhodoliths (cryptofauna) in March 2003. Rhodoliths and Sargassum horridum had the highest cover of all organisms within the 0.5-km2, 2-8-m-deep cobble-sand site. A total of 29 species of seaweeds, 40 taxa of benthic invertebrates, and 33 species of fish were sampled in transects and quadrats. Macroalgal and fish diversity were similar between sampling times as a result of loss and replacement of taxa, but benthic invertebrate diversity declined without replacement from March to October. Rhodolith cover was similar at both sampling times. The cover and density of S. horridum were highly seasonal, and the non-rhodolith flora changed from abundant S. horridum (35% cover) in March to abundant red algal turf in October (22% cover). The sea urchin Arbacia incisa, tunicates, and polychaetes were the most abundant epibenthic invertebrates in March, but declined by October, the former to zero. Grunts (Haemulon maculicauda) and porgies (Calamus brachysomus) were the most abundant fish at both sampling times, but there were large temporal changes in some other species, especially schooling fishes. Rhodolith density in March was 24 ind m-2, with numerous individuals >8 cm diameter. Fifteen rhodoliths from a range of size classes contained 114 cryptofaunal taxa with an average of 40 taxa /individual in the largest rhodoliths. These results show the importance of rhodolith habitat to diversity, the large temporal changes in some assemblages, and the exceptionally high diversity of this subtropical community.
Maerl is a type of rhodolith, found in ecologically important beds of high conservation value; a major conservation objective is to establish growth rates. Maerl shows internal banding of controversial periodicity that may contain a high-resolution record of palaeoceanographic-palaeoclimatic data. To investigate growth rates and banding periodicity, we used the vital stain Alizarin Red in combination with scanning electron microscopy (SEM). Three maerl species, Phymatolithon calcareum, Lithothamnion corallioides and L. glaciale, were collected from maerl beds in Ireland. Following staining, maerl was grown in three controlled temperature treatments and at two depths in the field (P. calcareum only), with Corallina officinalis as a control for the stain. Alizarin Red was shown to be a suitable marker for growth in European maerl species and for C. officinalis. The average tip growth rate of P. calcareum from Northern Ireland at 10 m depth and under constant laboratory conditions was c. 0.9 mm yr(-1), double the rates observed at 5 m depth and in L. corallioides. Our measurements and re-examination of reported data allow us to conclude that the three most abundant maerl species in Europe grow about 1 (0.5-1.5) mm per tip per year under a wide range of field and artificial conditions. Internal banding in temperate European maerl revealed by SEM is a result of regular changes in wall thickness; the approximately monthly periodicity of bands in field-grown specimens is consistent with previous suggestions that they may be lunar. The potential for maerl banding to be a high-resolution record of palaeoclimatic and palaeoenvironmental change could be realized with this vital stain in conjunction with isotopic or microgeochemical analyses.
Massive influxes of waste water and sludge di scharges from treatment plants increased the percentage of sludge and the organic matter content in the sediment off the coast of Barcelona (Western Mediterranean Sea). A total of 22 species of cumaceans were recorded in this area at depths between 5 and 70 m. The distribution of these species was essentially depth-depenclent, though at the deeper stations the distribution pattern was significantly correlated with the organic matter content. This aspect was particularly pronounced in the case of lphinoe rhodaniensis. which attained maximum density levels of up to 573 ind. m-2 in the vicinity of the two major sites of eutrophication. Moreover. the increased percentage of sludge facilitated colonisation of species such as Leucon affinis and Leucon siphonatus. which have been typically considered as bathyal species.
Gelidiella calcicola sp. nov. (Gelidiales, Gelidiaceae) is described from plants growing on loose-lying subtidal coralline algae and shells on southern, western and northern shores of the British Isles, and from Roscoff in Brittany, France. The species forms narrow, creeping axes attached at intervals by peg-like rhizoidal holdfasts. Irregularly pinnate branches arise at the points of attachment, arc downwards, and become attached and pinnately branched. No erect axes are formed; in all other described species of the genus Gelidiella at least some erect axes are formed from the creeping base. Internal rhizines, considered to be characteristic of all the genera of the Gelidiales except Gelidiella, are present in the medulla, but only at the attachment points. Surface cortical cells are large and usually arranged in chevron-like transverse rows. Tetrasporangia, formed only in the winter months, occur in lateral stichidia in chevron-like rows of 8–10 per row; they are spherical and apparently tetrahedrally or irregularly divided. Gametangial and carposporangial plants have not been found; these are known in only one species of the genus. Attempts to induce reproduction in vegetatively isolated plants in culture by subjecting them to a wide range of temperature and photoperiodic regimes in various enriched sea-water media strengths were unsuccessful. The new species is compared with Gelidium pusillum from the British Isles, and with the 21 previously described species of Gelidiella. The status of the family Gelidiellaceae is assessed and it is concluded that it should be merged with the Gelidiaceae. Some doubts are expressed as to the validity of the criteria used to delimit the genus Gelidiella.
A new species of Listriella is described and figured from maerl deposits in Kilkieran Bay, Co. Galway. The holotype of the only other British species is figured for comparison. The amphipod fauna of Kilkieran Bay (Co. Galway) maerl is compared with that of Eddystone shell gravels.
This paper provides a critical review of the main issues regarding the scientific principles underlying environmental monitoring of marine aquaculture operations and makes recommendations relevant to the implementation of best practice for the management of aquaculture in Europe. Given that a variety of cultured species and approaches are adopted in Europe, it is not possible, or indeed desirable, to devise prescriptive guidelines. Instead, this paper reviews how science informs monitoring and provides a framework for the development of a monitoring strategy of marine aquaculture operations that is flexible enough to be applicable to a variety of locations, species and situations.
Traditionally environmental monitoring has concentrated on a few key physical and chemical variables and organisms. The trend now, however, is towards whole-system environmental assessment (e.g. CEC 2000; Osparcom 1998), including considerations of the assimilative capacity of specific systems and their ability to absorb and dilute perturbations. Against this background this paper addresses the following specific objectives:
• review of the rationale and scientific principles underlying current environmental monitoring with specific reference to marine aquaculture;
• evaluation of the links between monitoring and regulatory criteria, specifically consideration of environmental quality objectives and environmental quality standards, and the role of environmental impact assessment;
• assessment of the role of codes of best conduct and practice, and environmental management systems in the management of aquaculture operations.
The paper concludes by proposing a set of recommendations which will contribute towards the sustainable management of aquaculture operations, through the implementation of a more focused approach to environmental monitoring.
In Scotland, Atlantic salmon Salmo salar cages are being moved out of areas with slow water movements, to disperse wastes and reduce impacts on benthic communities. This first study of the effects of fish farms on maerl beds (red algal coralline gravels of high conservation importance) demonstrated major impacts on the benthos, even in strongly tidal areas. SCUBA surveys of 3 fish farms located over maerl revealed a build-up of waste organic matter and 10 to 100-fold higher abundances of scavenging fauna (e.g. Necora puber, Pagurus bernhardus) than on 6 reference maerl beds. Visible waste was noted up to 100 m from cage edges, and all 3 farms caused significant reductions in live maerl cover, upon which this habitat depends. Near-cage infaunal samples showed significant reductions in biodiversity, with small Crustacea (ostracods, isopods, tanaids and cumaceans) being particularly impoverished in the vicinity of cages, and significant increases in the abundance of species tolerant of organic enrichment (e.g. Capitella spp. complex, Ophryotrocha hartmanni). Relocation of fish farms to areas with strong currents is unlikely to prevent detrimental effects to the structure and organisation of the benthos, and `fallowing' (whereby sites are left unstocked for a period of time to allow benthic recovery) is inadvisable where slow-growing biogenic habitats such as maerl are concerned, as this may expand the area impacted.
Maerl community respiration, photosynthesis and calcification were measured seasonally in the Bay of Brest (France). The dynamics of oxygen, carbon and carbonate fluxes at the water-sediment interface were assessed using benthic chambers. Community respiration (CR) fluctuated in accordance with the seasonal changes in water temperature, from 1.5 mmol C m(-2) h(-1) in winter to 8.7 mmol C m-2 h-1 in summer. Mean gross community production (GCP) varied significantly among seasons, according to incident irradiance and temperature, from 3.4 mmol C m(-2) h(-1) in winter to 12.7 mmol C m(-2) h(-1) in summer. Mean annual P-max for the P-E curve was estimated to 13.3 mmol C m(-2) h(-1). Carbonate precipitation only occurred during light incubations and varied seasonally from 0.7 mmol CaCO3 m(-2) h(-1) in winter to 4.2 mmol CaCO3 m(-2) h(-1) in summer. Mean annual Pmax was 3.2 mmol CaCO3 m(-2) h(-1). Annual CR was estimated to 407.4 g C m(-2) yr(-1), and GCP, to 240.9 g C m(-2) yr(-1). Maerl communities are, therefore, heterotrophic systems (GCP:CR = 0.6), and are a source Of CO2 for surrounding environments. In addition, CO2 released by calcification averaged 39.2 g C m(-2) yr(-1). Maerl community annual carbonate production was estimated to 486.7 g CaCO3 m(-2) yr(-1); they are therefore one of the most important carbonate producers in shallow coastal waters.
In maerl beds, architectural complexity is a physical factor which can explain the high specific diversity, and these habitats are moreover characterized by a high functional diversity. The physical structure of this habitat consists in providing refuges for a lot of predators and biotic interactions founded on predation, disturbance, competition... prevent any ressources monopolisation by only a few dominating species. Comparison of macrobenthic structures on homogeneous muddy bottoms and maerl beds in the Bay of Brest gives a first explanation to this high diversity. A second comparison between Control and Impacted maerl beds stations (eutrophication in the northern basin of the Bay of Brest, turbidity by direct exploitation of coralline algae in Glenan) suggests the existing links between specific and functional diversities.
A study was undertaken of the crustacean community associated with maerl habitats in Mannin Bay, Ireland. Based on a visual classification of sedimentary fractions, eight sedimentary facies could be distinguished. These ranged from live maerl banks and seagrass-covered live maerl banks in the shallow, low energy parts of the inner bay to maerl debris facies, mixed with varying proportions of sand, mud and shell gravel in the more exposed, high energy, parts of the bay. Amphipoda dominated the crustacean fauna, accounting for more than 95% of total numerical abundance. Overall, the crustacean fauna occurring in the studied maerl habitats is similar to the fauna occurring in subtidal gravel habitats, with little evidence of elective species. Only the mud-maerl debris facies and the seagrass-covered live maerl banks appear to harbour a relatively different crustacean fauna from the remainder of the sedimentary facies. These differences were mainly changes in the numerical abundance of dominant species, rather than species displacements.
Benthic monitoring efforts in the vicinity of a Pacific threadfin Polydactylis sexfilis mariculture venture have, allowed us to examine eutrophic effects on the infaunal community. Polychaete infaunal communities from 2 sites near the point source were compared to 2 control stations beyond the range of fish feed and wastes. Regression analysis indicated significant decreases in Shannon-Weiner diversity over time and near the effluent source. Non-metric multidimensional scaling (nMDS) showed a progression of species succession and turnover at impacted sites but relatively unchanging polychaete communities at control sites. An analysis of similarity (ANOSIM) indicated significant differences between community structures at impacted and control sites but less obvious differences over time. An abundant and regionally widespread polychaete Pionosyllis heterocirrata had disappeared from impacted sites. Increasing abundances of 2 opportunistic polychaetes, Capitella capitata (complex) and Ophryotrocha adherens, resulted in decreasing Shannon-Weiner diversity values (H') at impacted stations. Expanding populations of C. capitata and O. adherens seem to be preceded by high densities of Myriochele oculata. These 3 species may represent an order of succession due to attrition by anoxia in Hawaiian waters. Deviation of the infaunal polychaete community at impacted sites resulting from the appearance of polychaete pollution indicators, low species richness resulting from the disappearance of ambient polychaete species and depressed community abundance reflect the effects of fish mariculture on the benthic community. Such effects may be diluted by the open-ocean location on the south shore of O'ahu, Hawai'i.
Macrobenthic invertebrate data from the San Pedro Shelf, California, were used to evaluate the Infaunal Trophic Index (ITI). The ITI is a numerical representation of the distribution of dominant feeding groups of benthic fauna that has been used to quantitatively model community response to organic material in the water column and/or substratum. Although ITI has been applied to various monitoring studies in the Southern California Bight and elsewhere and is used as a regulatory tool in management decisions, the index has not received detailed scrutiny. Long-term (1977-1993) benthic infauna data and associated sediment geochemistry (particle size, organic and inorganic contaminants) were used to examine variation in ITI. Results indicated that ITI was affected by water depth, granulometry, distance from an outfall of wastewater to the ocean, year and season, and numerically important species. Variation in ITI feeding groups was also affected by year, season, and station. We argue for a more critical application of ITI in regulatory protocols for management decisions in ocean water quality.
Detailed faunal data relating to a sublittoral survey of kelp holdfasts (Laminaria hyperborea (Gunn.) Fosl.) in northeast Britain are presented. These data have been ordered by multivariate statistical techniques. Analytical strategy-is outlined and results pertaining to the classificatory techniques of association analysis (ASOC), predictive attribute analysis (PRED) and divisive information analysis (DINF) using qualitative data are given. Normal and inverse hierarchies wree computed using ASOC and DINF and used to construct two-way tables. Recognition of environmentally definie species assemblages is possible from a consideration of particular analyses. Taking into account certain methodological and sampling limitations, a definition of groups of ubiquitous, clear-water, turbidity indifferent and turbid water species may be recognized; the significant species for which purposes are only one-third of the total number considered.A primary correlation between the local composition of the holdfast fauna and turbidity is indicated. Subsidiary pollution effects cannot be ruled out but their definition becomes complicated by the intervention at lower levels of heterogeneity of other correlating factors, e.g., holdfast morphology. The danger of attributing causal relationships to statistical correlations is stressed throughout.
The overriding metabolic advantages of aerobic as compared with anaerobic respiration have resulted in its use by the majority of multicellular organisms. However, in some habitats oxygen is limiting to such an extent that anaerobic respiration becomes a necessity for survival. It has frequently been demonstrated that the extent of anaerobiosis depends, obviously, on the degree of oxygenation of the environment (see reviews by von Brand, 1944, 1945; Beadle, 1961). Hence, not only are there entirely anaerobic organisms but many other organisms exist which, in times of anoxic stress, are able to undergo a partial, or facultative, anaerobiosis. Lindeman (1942) discovered that, at low temperature, aquatic chironomid larvae could survive the entire winter anaerobically in the anoxic hypolimnion of freshwater lakes. Similarly, but to a lesser extent, pond-living crayfish of the genus Cambarus are more resistant to low oxygen concentration than stream-living individuals (Park, 1945). Walshe (1948) has also been able to establish a similar relationship in a group of stream and ditch dwelling chironomid larvae.
Following cessation of fish production at a fish farm site in Loch Cretan, Scotland, a study of the recovery of the benthic environment was undertaken. Sediment samples for macrofauna and geochemical parameters (redox potential, organic carbon, oxygen flux) were collected over a period of 15 months from three stations following a gradient of impact from the former fish farm site. The data collected were analysed by a combination of uni-and multivariate statistical methods. The macrobenthic community at the two stations furthest from the fish cage site showed signs of recovery with time in terms of indicator species, number of species and abundance, being, however, still moderately to slightly disturbed at the end of this study. At the station nearest to the former fish cage site, recovery of the macrobenthic community was also evident, but this station was still highly impacted 15 months after fish production ceased, with opportunistic species dominant. Fifteen months after fallowing, highly reduced conditions were still persistent in subsurface sediments at the stations on the periphery of the former fish cage site. Bulk sediment organic carbon, although an indicator of a spatial gradient, was not found to be a significant indicator of recovery. Combinations of different environmental parameters appear to affect different stages of benthic recovery with sediment oxygen uptake as the main observed parameter conditioning early stages of macrobenthic succession. (C) 2004 Elsevier B.V. All rights reserved.
Maerl beds are little studied shallow marine habitats that have a patchy distribution around the British Isles. They are mixed sediment deposits built by a surface layer of slow growing coralline seaweeds that are of international conservation significance. Baseline information is provided on the high diversity and abundance of mollusc assemblages associated with Scottish maerl deposits. Commercial extraction and the use of towed demersal fishing gears kills the plants upon which survival of this habitat depends. The molluscan fauna of a site impacted by scallop dredging is compared with that of an unimpacted site. The need to conserve maerl habitats is highlighted as there is concern over the extent to which maerl beds are being disturbed in Europe and how activities such as scallop dredging affect the ecology of these fragile nearshore habitats.
Burrows inhabited by Upogebia deltaura (Crustacea: Thalassinidea) were studied over a two-year period on two maerl beds at 10 m below Chart Datum (CD) in the Clyde Sea area, Scotland. Labelled burrows proved to be stable features on each ground, with animals able to withstand the impacts of scallop dredging and storm disturbance by re-building the damaged upper sections of their burrows. Resin casts excavated using an air-lift showed that these burrows were inhabited by single individuals. Burrows were deeper, larger and more complicated than was previously thought typical for U. deltaura and other members of the genus. Mapping of burrow systems revealed average densities of 2.9 ind m 72 with up to ten openings m 72 . These elusive animals were the deepest burrowing megafauna (to 68 cm) and the most abundant large crustaceans within the maerl bed habitat.
Galathea intermedia is common, but cryptic, on Clyde maerl deposits where it lives in small groups of mixed sex and age, sharing shelters (typically dead Dosinia shells) to avoid predation. Its appearance is marked by six iridescent blue spots which may play an important role in intra-or interspeci¢c interactions. Anomuran decapod crustaceans of the genus Galathea are widespread in rocky/gravelly subtidal areas around north-western European coasts (Zariquiey Alvarez, 1968). Recent interest in the group has been stimulated by the growing commercial importance of squat lobsters as the target of an expanding European ¢shery. However, the biology and ecology of these animals remain poorly studied (De Grave & Turner, 1997). Of the six species of Galathea known to occur in coastal waters (to 200 m) around the British Isles (Howson & Picton, 1997), ¢ve have been recorded in the Clyde Sea area (Allen, 1967). Our attention was drawn to Galathea intermedia Liljeborg, the smallest of these species (carapace length 58.5 mm), during in situ observations between 6 and 15 m depth on two maerl grounds in the Clyde Sea (Stravanan Bay 55845.3301 H N 0584.2601 H W and Creag Gobhainn 56800.6001 H N 05822.2000 H W) using SCUBA. Galathea intermedia were found in small groups, hiding in the interstices of maerl fragments or with up to three animals sharing the shelter of dead Dosinia exoleta (L.) shells. These bivalve shells were common on the sediment surface of the study sites having fallen prey to the star-¢sh Marthasterias glacialis (L.) and Asterias rubens L. (J.M.H.-S., personal observation). A previously unrecorded feature of G. intermedia is its very conspicuous anterior coloration pattern consisting of sineon' blue spots in the frontal region of the head (a triangular epistomial patch medially above a small labral spot, a pair of lateral spots beneath the eyes at the base of the antennae and a pair of spots on the geniculate carpopodite of the second maxilliped endopodite). Observations on the incidence of this coloration were made on 86 G. intermedia, with carapace lengths from 3.4 to 7.9 mm, measured from the tip of the rostrum to the posterior mid-dorsal margin. These animals were collected by removing maerl sediment and dead Dosinia shells from a 5 m 2 area at 10 m depth in Stravanan Bay on 25 September 1997. The squat lobsters clung to the collected substratum and few escaped. Previous UK records of G. intermedia show that it can be very common on gravelly sediments in the shallow sublittoral, with few records beyond 50 m depth (Marine Biological Association, 1957; Bruce et al., 1963; Crothers, 1966; Allen, 1967). The population density of G. intermedia recorded here on coralline gravel (at least 17 ind m 72) is within the range of 3.0^16.6 ind per 0.25 m 72 encountered by Samuelsen (1970) at a similar depth (7^9 m) in Norway. He also found that this species was contiguously distributed with its abundance being positively correlated with the amount of coarse substratum. When placed in aquaria, the squat lobsters hid amongst the shell/maerl substrata. Animals of various sizes settled near to one another with equanimity and began a routine of feeding and self-grooming (recorded using a Panasonic F10 video-camera (¢lm rate 25 ¢elds s 71) ¢tted with a 50 mm Pentax macro-lens and connected to a Panasonic AG6200 video-recorder). The bright blue iridescent markings were strikingly apparent in en face view (Figure 1A). The largest and most conspicuous markings (visible in situ to the naked eye of divers) were on the carpopodite of the second maxilliped endopodite above due to limb £exure, but anatomically below a contrasting red/brown patch on the propodite (Figure 1A,B). These features are lost when the animals are ¢xed in alcohol or formalin, which probably explains why they have been overlooked in previous descriptions of the species (e.g. Liljeborg, 1851; Bouvier, 1940; Zariquiey Alvarez, 1968). The spacing and size of the markings increased with size of the animal but there were no obvious di¡erences in their pattern or intensity depending upon the sex, maturity or egg-bearing status of individuals as this con¢guration of markings was present on all collected specimens. A few individuals moulted in captivity and the markings were seen before and after ecdysis. Filmed observations in aquaria showed that G. intermedia used its chelae to tear food when presented with scraps of crab £esh but that scavenging was not its normal feeding mode, as shown with G. squamifera Leach, G. strigosa (L.) and G. dispersa Bate (Nicol, 1933). The ability of G. intermedia to detect carrion appeared to be limited, as scraps were ignored if lying beyond two body lengths from the animal. The animals fed primarily on detritus, sweeping ¢ne particles from the substratum using the setose third maxillipeds and passing material on to the second maxilliped and thence to the mandibles. The highly re£ective spots on the second maxilliped endopodites moved constantly as the animals fed or groomed the head region, this movement ceased when animals were disturbed with forceps and when conspeci¢cs met. Given the shallow-water and contagious distribution of G. intermedia, the highly re£ective blue spots may have a function in communication. Their pattern and colour (or contrast in colour) may provide a means of intraspeci¢c recognition
Maerl beds are highly biodiverse biogenic substrata that have been receiving increasing attention in the last decade. Although maerl beds represent important nursery areas for commercial fishes and molluscs, little is known on the trophic web of their communities. Community structure parameters of maerl bed of the Bay of Brest (species richness, abundance, biomass and dominating species) were studied in parallel with the carbon and nitrogen isotopic composition of their main benthic species (macrofaunal, and megafaunal organisms) in order to assess the trophic levels and differences in the potential food sources of maerl inhabitants. The major potential sources of energy were identified to originate either from epiphytic macroalgae and microphytobenthos both growing on maerl thalli, together with sedimenting (sedimentary) particulate organic matter (POM) originating from the water column. The majority of the macro- and megafaunal organisms investigated were filter feeders, selective-deposit feeders and predators/scavengers. Filter feeders fall into three different groups representing different trophic pathways (i) sponges feeding directly on POM (water column filter feeders I), (ii) ascidians and holothurians feeding on POM and probably captured pelagic preys (water column filter feeders II), and (iii) filter feeding molluscs and crustaceans were hypothesised to feed on microphytobenthos or on decaying sedimented POM (Interface filter feeders). Selective deposit feeders were also divided into two subgroups. Carnivores were also distinguished between those with scavenging habits and true predators. Coupling of the trophic levels observed with the community biomass structure revealed that most of the benthic biomass derives its food from detritic sedimented POM and/or microphytobenthos, with interface filter feeders (23% of the biomass), selective deposit feeders (12%). Carnivores made up to 14% of the total biomass. Generally stable isotopes ratio mean values overlap and cover a large range within feeding types, indicating a strong overlap in food sources and a high degree of complexity of the food web presumably due to the diversity of the potential food sources.
Carbonate frameworks secreted by phototrophic organisms within the Arctic Circle are not well documented. Underwater surveys of the inner-shelf off Troms, northern Norway (70°N), reveal extended fixed algal build-ups which are fringed by rhodolith belts affected by storms. Reefal growth by coralline algae under temperature and light regimes of extreme seasonality is made possible because of a decoupling of carbon fixation during summer and utilization of stored carbon during the period of winter darkness. Although the annual growth of the framework constructing algae is comparatively low, the annual carbonate production rate is similar to subtropical-tropical counterparts because of a remarkably high standing stock. Early diagenetic alteration is restricted to intraparticle cementation processes which start in vivo. Bioerosional destruction is the dominant control on the preservation of high latitude build-ups. Preservation of Holocene autochthonous coralline algal biostromes is enhanced by rapid burial during storm events. Redeposition during storms is the most important process in forming a distinct sedimentary facies zonation.
Rhodoliths (maërl) are widely distributed in the worlds' oceans and have an excellent fossil record. Individuals are slow growing, may be long lived (>100 years), and are resilient to a variety of environmental disturbances. Their external morphology and internal growth bands are potential archives of environmental variation at scales of within years to tens of years. At high densities, these free-living non-geniculate coralline algae form rhodolith beds, communities of high diversity that can be severely impacted by resource extraction.
To validate a resuspension model of particulate material (salmonid farm wastes), a UV fluorescent particle tracer was selected
with similar settling characteristics. Tracer was introduced to the seabed (water depth ≈30 m) and sediment samples taken
on days 0, 3, 10, 17 and 30 to measure the horizontal and vertical distribution of tracer in sediments. A concentric sampling
grid was established at radii of 25, 50, 100, 150, 200, 400, 700 and 1, 000 m from the source on transects 30° apart. The
bulk of the deployed tracer was initially concentrated in an area 25 m radius from the release point; tracer was observed
to steadily decrease to zero over a period of 30 days. In a 200 m region measured from the release point in the direction
of the residual current, the redeposition of tracer was low. A Lagrangian particle tracking model was validated using these
observed data by varying resuspension model parameters within limits to obtain the best agreement between spatial and temporal
distributions. The validated model generally gave good predictions of total mass budgets (±7% of total tracer released), particulary
where tracer concentrations were high near the release point. Best fit model parameters (critical erosion shear stress=0.018
N m−2, erodibility constan=60 g m−2 d−1) are at the low end of reported parameters for coastal resuspension models. Such a low critical erosion shear stress indicates
that the frequency of resuspension and deposition events for freshly deposited material is high.
Shallow-water macrofaunal communities have been studied in the Bay of Brest in order to estimate the impact of the main sources of urban, industrial, harbour and agricultural perturbations. Sampling stations were located on the shallow muddy grounds, between 0 and 5 m depth and in the estuaries.The analytic method of evaluation was based on the recognition of ecological groups of different sensitivity to organic matter overload. Their relative abundances allowed identification of stages of perturbation including eutrophication. The heavily polluted areas were easily identified in the northern basin, along Brest city and its harbour complex. With respect to the latter, opposite situations were shown for the northern and southern basins (the northern being eutrophicated). The double statistical analysis revealed that the first factor structuring the communities was anthropogenic perturbations, the second was the edaphic factor.
The spatial extent and timing of the impact of fish farms on the distribution and performance of a Posidonia oceanica meadow were examined in an embayment of the south-eastern coast of Spain (Hornillo Bay, Murcia). Changes in seagrass distribution were determined using available seagrass mapping (from 1988, i.e., before the onset of aquaculture activities and 1998) and by successive sampling in 1994 and 1998. Environmental variables (light attenuation coefficient, water-column dissolved nutrients and organic content of sediments) together with plant performance (shoot biomass, leaf growth rate, photosynthetic activity, carbohydrate reserves, the number of leaves per shoot, epiphyte loads and herbivore pressure) were measured in plants affected by organic discharges, and were compared with those found in reference healthy plants over an annual growth cycle. Since the onset of fish farm activity, 11.29 ha of P. oceanica meadow has been completely lost and 9.86 ha significantly degraded, thus resulting in a total affected area which accounts for about 53% of the former meadow, or 7-fold the fish farming area. Unequal propagation of seagrass die-off or degradation reflects the relevance of local factors such as depth and hydrodynamism on the true extent of fish farm impact. Water transparency decreases and dissolved nutrient and organic content of sediments increases in the vicinity of cages compared to distant reference stations, thus supporting the notion of environmental gradients caused by the organic release from cages, which spreads outwards. Shoot size, leaf growth rate and the number of leaves per shoot in plants close to the fish farm decreased. Moreover, low leaf growth and low rhizome carbohydrate concentration (always relative to that found in an undisturbed area) indicated carbon budget imbalances. Since light reduction in the affected area was only modest (31% of light reaching the sea surface, while at the same depth this figure was 39% at the reference site), and light availability was well above the minimum requirement estimated for this species, neither this factor nor epiphyte overgrowth (epiphyte load was lower in the affected area) seem to explain such carbon imbalances or the observed meadow regression. Alternatively, the high herbivore pressure found in the affected zone suggests that overgrazing is one of the main causes of decreasing shoot sizes and hence of carbon imbalance, reduced growth and shoot mortality. The impact of fish farms on seagrasses, therefore, seems to be highly variable and depends on complex interactions between a large number of processes.
Maerl is a general term used for loose-lying subtidal beds of nodular coralline red algae. Maerl beds support high associated invertebrate and algal biodiversity, and are subject to European and UK conservation legislation. Previous investigations have shown European maerl to be ecologically fragile due to growth rates of approximately 1 mm per year. However, these very slow growth rates have hampered attempts to determine the key ecological requirements and sensitivity characteristics of living maerl. In this study, photosynthetic capacity determined by pulse amplitude modulated (PAM) fluorometry was used as a diagnostic of stress caused by various environmental conditions. Maerl species were exposed to a range of temperatures, salinities and light levels and to burial, fragmentation, desiccation and heavy metal treatment. Maerl was not as susceptible as previously assumed to extremes of salinity, temperature and heavy metal pollution, but burial, especially in fine or anoxic sediments, was lethal or caused significant stress. These data indicate that the main anthropogenic hazard for live maerl and the rich communities that depend on them is smothering by fine sediment, such as that produced by trawling or maerl extraction, from sewage discharges or shellfish and fish farm waste, and sedimentation resulting from disruption to tidal flow.
Pesticides are used extensively in the finfish aquaculture industry to control sea lice infestations on farmed salmon. The most prevalent method of use is to enclose a net pen with an impervious tarpaulin and mix a pesticide solution within that enclosure. After treatment for short periods (1 h) the pesticide solution is released to the environment. Concerns have been raised that there is a potential risk to non-target aquatic organisms from those releases. The fate of dispersing pesticide solutions was measured after six simulated treatments in the Lower Bay of Fundy, New Brunswick. Three simulated treatments were done with azamethiphos and three with cypermethrin. Rhodamine dye was added to all pesticide solutions in order to facilitate tracking of the dispersing plume through real-time measurements of dye concentrations by a flow-through fluorometer coupled with a differential global positioning system (DGPS). Water samples were obtained from within the plumes at various times after release and analysed for pesticide content and toxicity to a benthic amphipod Eohaustorius estuaris. Dye concentrations were detectable for time periods after release which varied from 2 to 5.5 h. Distances travelled by the dye patches ranged from 900 to 3000 m and the dye concentrations at the final sampling period were generally 1/200-1/3000 the pre-release concentrations and cypermethrin concentrations were generally 1/1000-1/2000 the pre-release concentrations. Cypermethrin concentrations in water samples were closely correlated with dye concentrations, indicating that dye analyses were an accurate surrogate for cypermethrin concentrations. Most samples taken after the releases of azamethiphos were not toxic to test organisms in 48 h exposures and none were beyond 20 min post-release. By contrast, almost all samples taken after the release of cypermethrin, even up to 5-h post-release, were toxic. Data indicate the potential to cause toxic effects over areas of hectares from a single release of cypermethrin.
Marine fish farming is increasing rapidly in the Mediterranean and in contrast to the Atlantic the coastal zone in the Mediterranean is characterized by clear waters with high transparency. This allows benthic primary producers such as the slow-growing seagrass Posidonia oceanica to grow at large depths at locations suitable for fish farming and generating a conflict between the conservation of these meadows and the growth of aquaculture operations in the Mediterranean. In this paper we review the current knowledge on environmental interactions between fish farming and benthic primary producers with particular focus on P. oceanica, as this seagrass is a key component along Mediterranean coasts. The recovery times of P. oceanica are very long, in the order of centuries, and losses of this species are thus considered to be irreversible at managerial time scales.
A new species of Stenothoe dana (Amphipoda, Gammeridea) from maerl deposits in Kilkeran Bay
A A Myers
Myers AA, McGrath D. 1980. A new species of Stenothoe dana
(Amphipoda, Gammeridea) from maerl deposits in Kilkeran Bay.
J. Life Sci. R. Dublin Soc. 2: 15-18.
Rhodoliths: Between rocks and soft places Diversity and natural history of a Lithothamnion muelleri-Sargassum horridum community in the Gulf of California Notes on the natural history of certain sand-dwelling Cumacea
Foster MS. 2001. Rhodoliths: Between rocks and soft places. J. Phycol. 37: 659–667 Foster MS, McConnico LM, Lundsten L, Wadsworth T, Kimball T, Brooks LB, Medina-López M, Riosmena-Rodríguez R, Hernández-Carmona G, Vásquez-Elizondo RM, Johnson S, Steller DL. 2007. Diversity and natural history of a Lithothamnion muelleri-Sargassum horridum community in the Gulf of California. Cienc. Mar. 33: 364–384 Foxon GEH. 1936. Notes on the natural history of certain sand-dwelling Cumacea. Ann. Mag. Nat. Hist. 17: 377–393
Conservation issues concerning the mollus-can fauna of maerl beds
Hall-Spencer JM. 1998. Conservation issues concerning the mollus-can fauna of maerl beds. J. Conchol. Spec. Publ. 2: 271–286
Biological monitoring of marine Special Areas of Conservation: A handbook of methods for detecting change. Joint Nature Conservation Committee
Hiscock K. 1998. Biological monitoring of marine Special Areas of
Conservation: A handbook of methods for detecting change. Joint
Nature Conservation Committee, Peterborough.
The Species Directory of the Marine Fauna and Flora of the British Isles and Surrounding Seas
M J Costello
D W Connor
Holmes JMC, Costello MJ, Connor DW. 1997. Crustacea. In: Howson
CM, Picton BE (eds.), The Species Directory of the Marine Fauna
and Flora of the British Isles and Surrounding Seas. Ulster
Museum and the Marine Conservation Society, Belfast and Rosson-Wye, pp. 153-224.
L M Irvine
Irvine LM, Chamberlain YMC. 1994. Seaweeds of the British Isles.
Vol. 1, Part 2B. British Museum (Natural History), London.
The marine fauna of New Zealand: Crustaceans of the order Cumacea
N S Jones
Jones NS. 1963. The marine fauna of New Zealand: Crustaceans of
the order Cumacea. N.Z. Oceanogr. Inst. Mem. 23: 9-80.