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Coastal shark fisheries in the PAcific - A brief overview of urrent knowledge

  • City of Cape Coral

Abstract and Figures

TSharks are found throughout the world in a wide variety of habitats and developed different life histories traits. Though sharks make up only a small percentage of the world’s recorded fish landings, they are extremely versatile and are a valuable resource. They are of primary importance in some regions of the world, sustaining important fisheries in some countries. Moreover, they have been, and are, a cheap but valuable source of protein for coastal communities dependent on subsistence fisheries. Humans can utilize much of the carcass for food or other uses. Sharks are exploited for their meat, fins, skin, liver, teeth, cartilage and other internal organs. Sharks are increasingly becoming endangered on a world-wide scale. The main reason for this is the demand for their fins which are being used for shark fin soup, an Asian delicacy. The extermination of Asian shark stocks has led to an increase in the price of the fins and this in turn has led Asian fishing operators to target sharks further and further away from their home countries, including the Pacific region. It has also contributed to the development of specific fisheries whereas elasmobranchs were so far essentially by-catches. From the point of view of Fisheries Departments of the Pacific countries, fishing pressure on reef sharks is not high, although no data is available for most of these countries. Assessment of the information collected through literature and questionnaires shows that Pacific shark catches seem to be poorly documented. This bibliographic study enhances the need for rapid assessment techniques.
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... Declines have also been reported in the waters of the Large Ocean Island States of the Pacific (Nadon et al. 2012;Clarke et al. 2013), the countries and territories of the western and central Pacific that have very small land masses relative to the size of their marine estates. However, information on sharks and rays is lacking for many of these Pacific states and territories, especially for coastal and deep-water species (Juncker et al. 2006;Clua and Planes 2014). This lack of information is a significant impediment to developing sustainable fishing and conservation policies across the region (Lack and Meere 2009). ...
... Due to this large knowledge gap, information was compiled from a diverse range of sources spanning anthropological records and ethnobiological research, natural science journal articles, grey literature and fishery improvement plans. Further information on elasmobranch diversity was also sourced from fisheries records, unpublished data, in-country informants and museum records (Akimichi 1978;Richards et al. 1994;Foale 1998;Juncker et al. 2006;Lack and Meere 2009;Gillett 2010;Banks 2014). Collectively, these sources documented 50 elasmobranch species in the Solomon Islands (Table 2), which included 43 confirmed or provisionally confirmed species and seven species that are likely to occur, given their distributions and available information (Table 1). ...
... In Marovo Lagoon, Western Province, shark fishing is conducted with heavy modern tackle (Hviding 1988). While data are limited, it seems likely that targeted shark fishing occurs in other communities, with the meat being consumed and fins sold for export (Juncker et al. 2006). As for many Pacific nations, collecting data from coastal fisheries is challenging and apart from specific datasets arising from specific projects, there are few long-term data on catch composition, fishing effort and landings. ...
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Sharks and rays are facing increasing anthropogenic pressure globally, including in the Pacific. However, data on their status and biodiversity are lacking for many Pacific Large Ocean Island States. This study aimed to construct a species checklist for the sharks and rays occurring in the Solomon Islands, review the human interactions with these species, and present a synthesis of their conservation status. Given the paucity of available data, a wide range of data sources were used including fisheries data, citizen science, and ethnobiological studies. Results were validated through a review process involving expert informants. Fifty sharks and rays were identified from the Solomon Islands, of which 20 are assessed as Vulnerable or Endangered on the IUCN Red List, 10 in the Convention on International Trade in Endangered Species, and 11 in the Convention for Migratory Species. The checklist also presents an eastwards range extension for the Endangered dwarf sawfish Pristis clavata. Fishing appears to be the main impact, though impacts from habitat loss and degradation are possible. This study provides a systematic synthesis and review of the biological diversity, uses, and cultural significance of Solomon Islands sharks and rays, and describes a process for assembling species checklists and reviews in data-poor contexts. However, this synthesis is based on limited information and a complete assessment of shark and ray status in the Solomon Islands will require primary fieldwork.
... In the Pacific, subsistence and artisanal fishing including for sharks date back thousands of years 37 , and are vital to food security 38 . Throughout Oceania, many subsistence and small-scale commercial fisheries for sharks exist, but catches are generally poorly documented 39 . Fiji is no exception. ...
... Sharks are not considered an important source of food in many parts of Fiji, mainly due to traditional food taboos which possibly serve to protect against dangerous marine toxins 39,55 . However, the meat from several species is known to be eaten in areas where it is not taboo 56 . ...
... Our findings show that domestic consumption is the main use of sharks caught both in targeted and bycatch shark fisheries. Taking sharks for personal consumption and/or selling them at local markets may be the result of local demand for alternative food fishes due to the loss of traditional fish stocks 39 . Hence, Fijian shark fisheries can be regarded as subsistence in nature, i.e. sharks are harvested for domestic consumption. ...
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Limited information is available on artisanal and subsistence shark fisheries across the Pacific. The aim of this study was to investigate Fiji's inshore fisheries which catch sharks. In January and February 2013, 253 semi-directive interviews were conducted in 117 villages and at local harbours on Viti Levu, Vanua Levu, Taveuni, Ovalau and a number of islands of the Mamanuca and Yasawa archipelagos. Of the 253 interviewees, 81.4% reported to presently catch sharks, and 17.4% declared that they did not presently catch any sharks. Of the 206 fishers that reported to catch sharks, 18.4% targeted sharks and 81.6% caught sharks as bycatch. When targeted, primary use of sharks was for consumption or for sale. Sharks caught as bycatch were frequently released (69.6%), consumed (64.9%) or shared amongst the community (26.8%). Fishers' identification based on an identification poster and DNA barcoding revealed that at least 12 species of elasmobranchs, 11 shark and one ray species (Rhynchobatus australiae) were caught. This study, which is the first focused exploration of the shark catch in Fiji's inshore fisheries, suggests that the country's artisanal shark fisheries are small but have the potential to develop into larger and possibly more targeted fisheries.
... cuvier) and hammerheads (S. lewini and S. mokkaran) were historically finned along with a range of whaler sharks (Carcharhinidae) 49 . Logbook data from 1995 -1996 indicates that sharks represent a significant portion (6.4 -13.6%) of the catch in the ETBF, with 33 -53% of sharks retained or finned, although this may be an underestimate due to under-reporting of catch 49 Regional SE Pacific shark fisheries At a regional scale, shark fisheries in the Pacific were generally low until the late 1970's, and intensification of targeted fisheries for shark finning increased in the 1980's 56,58 . Prior to the introduction of pelagic long-line and industrial fisheries in the mid 1980's -mid 1990's, shark fisheries in the SW Pacific region were mostly small-scale artisanal fisheries relying on traditional fisheries methods [58][59][60][61] . ...
... Logbook data from 1995 -1996 indicates that sharks represent a significant portion (6.4 -13.6%) of the catch in the ETBF, with 33 -53% of sharks retained or finned, although this may be an underestimate due to under-reporting of catch 49 Regional SE Pacific shark fisheries At a regional scale, shark fisheries in the Pacific were generally low until the late 1970's, and intensification of targeted fisheries for shark finning increased in the 1980's 56,58 . Prior to the introduction of pelagic long-line and industrial fisheries in the mid 1980's -mid 1990's, shark fisheries in the SW Pacific region were mostly small-scale artisanal fisheries relying on traditional fisheries methods [58][59][60][61] . ...
... These include sea cucumbers, various species of shellfish and shark fins. Shark fins have been a long-term cash product in both PNG and the Solomon Islands (Juncker, Robert, & Clua, 2006). Shark fins contain proteinaceous fibers highly prized for use in shark fin soup. ...
Purpose: To critically assess engagements with capitalism in coastal fisheries development, considering their success or otherwise for coastal villagers. Approach: Using field research and written reports of projects and the concept of 'social embeddedness' we analyse two fisheries development projects as local instances of capitalism. Findings: Coastal peoples in the Pacific have been selling marine products for cash since the earliest days of contact with both Europeans and Asians. Since the 1970s, there have also been fisheries development projects. Both types of engagement with capitalism have had problems with commercial viability and ecological sustainability. One way to understand these issues is to view global capitalist markets as penetrating into localities through the lens of local cultures. We find, however, that local cultures are only one factor among several needed to explain the outcomes of these instances of capitalism. Other explanations include nature, national political and economic contexts, and transnational development assistance frameworks. The defining features of 'local capitalisms' thus arise from configurations of human and non-human, local and outside influences. Social implications: Development project design should account for local conditions including: 1) village-based socioeconomic approaches, and 2) national political economic contexts, and 3) frameworks that donors bring to projects, and 4) (in)effective resource management. Originality/value of paper: The paper builds on years of experience of the authors across multiple projects. The analysis provides a framework for understanding problems people have encountered in trying to get what they want from capitalism, and is applicable outside the fisheries sector. Category: research paper
... Like in most developing countries, the coastal subsistence and commercial fisheries are data-poor 59 . Onboard observers only operate on a small fraction of Fiji's industrial offshore fishery 17,18 , while the coastal fisheries are virtually unmonitored 52,60 , so that the combined capture of sharks is greatly underreported and/or underestimated 61 . As involvement of local leaders has proved to be effective for collecting reliable fisheries data from local fishermen in other locations 62 , we suggest that traditional and religious leaders be involved to facilitate data collection on the level of exploitation in Fiji. ...
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Sharp declines in numerous shark populations around the world have generated considerable interest in better understanding and characterising their biology, ecology and critical habitats. The scalloped hammerhead shark (SHS, Sphyrna lewini) is subject to a multitude of natural and anthropogenic threats that are often exacerbated within the coastal embayments and estuaries used during SHS early life stages. In this study, we describe the temporal and spatial distribution, age class composition, and reproductive biology of SHS in the Rewa Delta (RD), Fiji. A total of 1054 SHS (including 796 tagged individuals; 101 of which were recaptured) were captured from September 2014 to March 2016 in the RD. A majority of the captures in this area were neonates and young-of-the-year (YOY) (99.8%). Significant seasonality in patterns of occurrence of both neonates and YOY individuals suggests a defined parturition period during the austral summer. Between the seven sampling sites in the RD we also found significant differences in SHS neonate catch per unit of effort, and average total length of individuals. According to the data, the RD is likely to represent an important nursery area for SHS up to one year of age.
... White Sharks are taken as incidental bycatch in commercial fisheries in New Zealand, Australia, New Caledonia, and Tonga and in directed bather protection programs in Australia (Reid and Krogh, 1992;Environment Australia, 2002;Department of Primary Industries and Fisheries, 2006;Duffy, 2004;Juncker et al., 2006;Green et al., 2009;Tirard et al., 2010;Chapter 23, this book). Our research emphasizes the ongoing need for regional cooperation on conservation and management of this species. ...
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The impact of fishing on chondrichthyan stocks around the world is currently the focus of considerable international concern. Most chondrichthyan populations are of low productivity relative to teleost fishes, a consequence of their different life-history strategies. This is reflected in the poor record of sustainability of target shark fisheries. Most sharks and some batoids are predators at, or near, the top of marine food webs. The effects of fishing are examined at the single-species level and through trophic interactions. We summarize the status of chondrichthyan fisheries from around the world. Some 50% of the estimated global catch of chondrichthyans is taken as by-catch, does not appear in official fishery statistics, and is almost totally unmanaged. When taken as by-catch, they are often subjected to high fishing mortality directed at teleost target species. Consequently, some skates, sawfish, and deep-water dogfish have been virtually extirpated From large regions. Some chondrichthyans are more resilient to fishing and we examine predictions on the vulnerability of different species based on their life-history and population parameters. At the species level, fishing may alter size structure and population parameters in response to changes in species abundance. We review the evidence for such density-dependent change. Fishing can affect trophic interactions and we examine cases of apparent species replacement and shifts in community composition. Sharks and rays learn to associate trawlers with food and feeding on discards may increase their populations. Using ECOSIM, we make some predictions about the long-term response of ecosystems to fishing on sharks. Three different environments are analysed: a tropical shelf ecosystem in Venezuela, a Hawaiian coral reef ecosystem, and a North Pacific oceanic ecosystem. (C) 2000 International Council for the Exploration of the Sea.
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Large-scale pelagic fisheries exploit a diversity of apex predators with a wide range of life history strategies. Exploitation of species with different life history strategies has different population and food web consequences. We explored the changes in predation that result from exploitation of a common species with a slow growth and low fecundity life history strategy (blue shark, Prionace glauca) with those that result from exploitation of a common species with fast growth and high fecundity (yellowfin tuna, Thunnus albacares) in the central Pacific Ocean. Longline fisheries directed toward billfishes and tunas also capture blue sharks as incidental catch. Mortality rates of sharks had been relatively low prior to the recent surge in finning that has resulted in a substantial rise in mortality of adult and subadult sharks in the last decade. We estimated the magnitude of changes in predation by populations of yellowfin tuna and blue sharks in response to longline fisheries that involve shark finning. Bioenergetics models for sharks and tunas were coupled to simple population models that account for changes in size-structure in response to fishery-induced mortality regimes in order to estimate predation responses to changes in fishing intensities. Our analyses demonstrate that blue shark populations are very sensitive to low exploitation rates, while yellowfin tuna populations are extremely robust across a wide range of exploitation rates by longline fisheries. Although predation rates by yellowfin tuna are 4-5 times higher than by blue sharks, longline fisheries have substantially greater effects on shark predation than on yellowfin tuna predation at the food web scale. Expected food web responses will be strongest where the unexploited biomass of long-lived species is high and predation is relatively specialized compared with other apex predators. Our analyses suggest that active management to reduce finning mortality in sharks will play an important role toward minimizing the effects of longline fisheries on the food web structure of the pelagic Pacific Ocean.
The sandbar shark, Carcharhinus plumbeus, is the most common large coastal shark in Virginia waters and is an important component of recreational and commercial fisheries along the east coast of the United States. Sandbar shark demographic analyses, using known and estimated life history parameters, including fishing mortality (F) at ages and levels estimated in a recent stock assessment, were used to estimate potential population growth and exploitation. Life history tables were constructed by using best estimates of natural mortality (M) of 0.11 or 0.07 for maximum ages of 30 or 60 yr, respectively. Natality was fixed at 2.1 female pups/yr. Fishing mortality (F=0.05, 0.10, 0.15, 0.20, or 0.25) was simulated to begin at age 8, 10, 15, 20, or 29. The annual population growth rate was highest under a "best-case" scenario of M=0.05 (1/2 best estimate) and maximum age of 30 yr, but was only 11.9%/yr. At M=0.11 for all ages, the population increase rate was 6.4%/yr, and the generation time was about 20 years. At higher juvenile mortality rates, the population growth rate decreased to 2.6%/yr. Adding fishing mortality at immature ages caused the population to decline unless F levels were <0.10 and 0.05 at maximum age = 30 and 60, respectively. It is apparent that sandbar shark populations will decline under any substantial fishing mortality on immature ages and that mature fish can be exploited only at very low levels.
Recent studies have shown that by 1991 the sandbar shark (Carcharhinus plumbeus) population along the Atlantic coast of the United States had declined in abundance to approximately 20% of its level in the late 1970s. This phenomenon allowed us to test the hypothesis that compensatory (density-dependent) growth occurred after severe population reduction. Age and growth of sandbar sharks were investigated by counting rings and back-calculating lengths at previous ages from vertebral samples collected in 1980-1981 and 1991-1992. The collections included 188 sharks from 1980-1981 and 412 sharks from 1990-1991 ranging in length from 51-172 cm precaudal length (PCL). All sharks were mature at lengths > 136 cm PCL. Minimum and maximum ring counts, which included a birth mark, were 1 and 25. Age at maturity was 15-16 years for both sample periods and both sexes. For sexes combined, the von Bertalanffy growth parameters were L∞=199 cm PCL, K = 0.057, t0=-4.9 years for the 1980-1981 sample and L∞=164 cm PCL, K = 0.089, t0=-3.8 years for the 1991-1992 sample. Statistical tests found significant differences between the two growth models. Significant differences in size at age and annual incremental growth of juveniles suggest a small increase in juvenile sandbar shark growth rate between the two sampling periods. However, age at maturity was unchanged between samples suggesting that any biological significance of a growth rate increase has not been realized.