No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Age and growth of the salema, Sarpa salpa (Osteichthyes, Sparidae), off the Canary Islands (East-Central Atlantic)
Abstract
Age and growth of the salema Sarpa salpa off the Canary Islands (east-central Atlantic) were studied by analysis of otolith structures in 1125 individuals sampled from January 1998 to December 1999. A concentric pattern of opaque and translucent zones was readily distinguishable in the otoliths; the opaque zone is formed during the summer, and the translucent one during the winter. The size of the fishes ranged from 119 to 452 mm total length, and their age was from 0 to 11 years. The parameters of the von Bertalanffy growth equation were: L∞ = 479 mm, k = 0.212 year -1, and t0 = - 1.08 year. A backcalculation method demonstrated the validity of using the otoliths to estimate age and growth of S. salpa.
... There are no data available on its growth for the Mediterranean population. The only studies on growth were made in the Canary Islands (Mendez-Villamil et al., 2001), and in the eastern South African waters (Van der Walt and Beckley, 1997). ...
... Along the central western coasts of Italy, salema spawn during two periods of the year, spring (March-May) and autumn (September-November). A similar reproductive cycle has been observed in the western Mediterranean (Corbera et al., 1998), while along the Tunisian waters (Sellami and Bruslè, 1975;Anato and Ktari, 1983), and in the Canary Islands (Mendez-Villamil et al., 2001), salema spawn during a single period that extends throughout the autumn and winter months. ...
... The oldest age estimate obtained in this study was seven years for females with a 33 cm TL. The growth performance of salema in the Mediterranean (φ = 2.59), esti-mated using the φ index of Munro and Pauly (1983), showed a growth rate dissimilar to those reported from South Africa (φ = 4.44: Van der Walt and Beckley, 1997), and the Canarian Archipelago (φ = 2.68: Mendez-Villamil et al., 2001). In the latter area salema seems to reach a larger length-at-age than in the Mediterranean. ...
The sexual maturation and the growth of the salema, Sarpa salpa (Linnaens, 1758), along the Italian Mediterranean coast (central Italy), were studied in fish (n = 105) killed incidentally by underwater explosions during the construction of Civitavecchia harbour in 1999 and specimens collected with trammel nets (n = 339). This species is characterized by a protandric hermaphroditism and the sex change process occurs between 24 and 31 cm TL corresponding to a wide range of ages (3-7 years). Size at maturity (L50) was 19.5 cm, at which almost all the individuals were males. Two distinct spawning periods were observed: one in spring, from March to May, and the other in autumn, from the end of September to November. During the first year, compensatory growth occurred in the individuals born in the two periods. An annual regular pattern of ring deposition was identified in the otoliths: the translucent ring was laid down during the winter months, while the opaque ring was formed during the summer months. Back-calculated lengths at age were used to estimate the parameters of the Von Bertalanffy growth equation which were: L∞ = 37.27 cm, K = 0.27 year-1 and t0 = -0.53 year. Salema showed isometric growth (b = 3.04; P = 0.84; t = 0.19).
... There are no data available on its growth for the Mediterranean population. The only studies on growth were made in the Canary Islands (Mendez-Villamil et al., 2001), and in the eastern South African waters (Van der Walt and Beckley, 1997). ...
... Along the central western coasts of Italy, salema spawn during two periods of the year, spring (March-May) and autumn (September-November). A similar reproductive cycle has been observed in the western Mediterranean (Corbera et al., 1998), while along the Tunisian waters (Sellami and Bruslè, 1975;Anato and Ktari, 1983), and in the Canary Islands (Mendez-Villamil et al., 2001), salema spawn during a single period that extends throughout the autumn and winter months. ...
... The oldest age estimate obtained in this study was seven years for females with a 33 cm TL. The growth performance of salema in the Mediterranean (φ = 2.59), esti-mated using the φ index of Munro and Pauly (1983), showed a growth rate dissimilar to those reported from South Africa (φ = 4.44: Van der Walt and Beckley, 1997), and the Canarian Archipelago (φ = 2.68: Mendez-Villamil et al., 2001). In the latter area salema seems to reach a larger length-at-age than in the Mediterranean. ...
The sexual maturation and the growth of the salema, Sarpa salpa (Linnaeus, 1758), along the Italian Mediterranean coast (central Italy), were studied in fish (n = 105) killed incidentally by underwater explosions during the construction of Civitavecchia harbour in 1999 and specimens collected with trammel nets (n = 339). This species is characterized by a protandric hermaphroditism and the sex change process occurs between 24 and 31 cm TL corresponding to a wide range of ages (3-7 years). Size at maturity (L50) was 19.5 cm, at which almost all the individuals were males. Two distinct spawning periods were observed: one in spring, from March to May, and the other in autumn, from the end of September to November. During the first year, compensatory growth occurred in the individuals born in the two periods. An annual regular pattern of ring deposition was identified in the otoliths: the translucent ring was laid down during the winter months, while the opaque ring was formed during the summer months. Back-calculated lengths at age were used to estimate the parameters of the Von Bertalanffy growth equation which were: L∞ = 37.27 cm, K = 0.27 year -1 and t0 = -0.53 year. Salema showed isometric growth (b = 3.04; P = 0.84; t = 0.19).
... W∞ from González et al. (1993) -From other model (Mendoza et al. 2020) -From personal database (2010 (Pauly 1980). L∞ and K from Villamil et al. (2001); Pajuelo and Lorenzo (2002); Lorenzo et al. (2002); ; and Domínguez-Seoane et al. (2006). ...
... -From empirical equation of Pauly et al. (1990). W∞ from Pallaoro et al. (1998);Villamil et al. (2001); Morato et al. (2001); Pajuelo and Lorenzo (2002); ; Monteiro et al. (2006) and Domínguez-Seoane et al., (2006). -Randall (1967); Man and Buxton (1992); Havelange et al. (1997); Lenfant and Olive (1998); Gonçalves and Erzini (1998) (Pauly 1980). ...
La presente tesis utiliza la modelización con “Ecopath with Ecosim” (EwE) como herramienta para describir el funcionamiento de los ecosistemas marinos costeros, incluyendo la pesca artesanal de la isla de El Hierro. Esta modelización se realiza con el objetivo de tener una aproximación al ecosistema litoral de la Isla y evaluar los efectos que tuvo la erupción submarina de 2011 en las comunidades litorales y en la pesca artesanal. Gracias a esta modelización se dibujan unos escenarios actuales y futuros con las tendencias en biomasas de los componentes de las comunidades litorales, los recursos pesqueros y el esfuerzo pesquero. Estos escenarios son útiles para evaluar las dinámicas de recuperación de las comunidades y los recursos pesqueros frente al evento catastrófico que supuso la erupción submarina y generan unas propuestas útiles para el manejo y gestión de los espacios naturales y los recursos pesqueros de la Isla.
... Much information on several aspects of this species was reported; mainly on food and feeding habits (Christensen, 1978;Anato and Ktari, 1983a;Verlaque, 1985Verlaque, , 1990Antolic et al., 1994;Havelange et al., 1997). In the Atlantic waters, studies were conducted on age and growth near the Canary Islands (Mendez-Villamil et al., 2001) and in the eastern waters of South Africa (Walt and Beckley, 1997) while age, growth, and reproduction of Salema have been reported on Portuguese coasts (Paiva et al., 2016). ...
... This species represents a significant part of the fish fauna (40-70% in biomass) (Francour, 1997;. In the last 15 years, this poorly studied species in the Mediterranean sea has attracted research interest because of first, its role as macro-grazer of sea grass (Velimirov, 1984;Havelange et al., 1997;Jadot et al., 2000;Jadot et al., 2002), second, its biology in order to develop a management strategy (Méndez-Villamil et al., 2001;Méndez-Villamil et al., 2002), and finally for its toxicity. (Spanier, 1988;Spanier et al., 1989;Chevaldonne, 1990). ...
Assessment of the freshness state of preserved Sarpa salpa under ice Abstract In this study we estimated by four appreciation methods the freshness state of Sarpa salpa species immediately captured. The TVB-N content is a tool of choice in the evaluation of fish species deterioration. The TBV-N content made possible to establish a narrow relation (R = 0.98) with the organoleptic examination (Freshness indexes). According to our results we suggest a value (28 mg N/100 g) as a limiting value of acceptance for the human consumption. Our results show that the bacterial development is the origin of the deterioration of freshness in the species studies, where Pseudomonas genus is the prevailing germ implied in the deterioration process. The storage time of Sarpa salpa should be limited to less than 6 days.
... A similar reproductive cycle has been observed in along the Tunisian waters (Sellami and Bruslè, 1975;Anato and Ktari, 1983), and in the Canary Islands (Mendez-Villamil et al., 2001), salema spawn during a single period that extends throughout the autumn and winter months. The size-at-maturity of males (21.1 cm) didn't differ significantly from the value observed in the Canary Islands 22.6 cm (Mendez-Villamil et al., 2002). ...
... Conducted studies on the reproduction period of P. acarne showed that this species had one long spawning season that extends from May to October in south Spain (Dominguez, 2000;Velasco et al., 2011) andPortugal (Neves Santos et al., 1995;Coelho et al., 2005) with an important peak in summer. In western Algerian coasts the monthly evolution of the different indexes showed that this sparidae had two spawning periods the first one between April to June with a peak in May and an autumnal period, between November and January with a peak in December a finding already described in Algiers Bay (Boufersaoui & Harchouche, 2015) for the same species, also in Sarpa genus (Corbera et al, 1996;Mendez, 2001;Criscoli et al, 2006). ...
The reproduction of Pagellus acarne caught in Oran Bay was studied. The samples used were sorted monthly from commercial catches of coastal trawlers operating in this area from April 2008 to July 2009. The overall sex ratio was in favor of females 1:1.27 and length frequency distribution according to sex revealed that the females were highly representative beyond 20.5 cm of total length presuming a sexual inversion already described for this sparidae. The estimated lengths at maturity (L m) were 12.8 cm for females and 16.0 cm for males. Two spawning periods were made out by the follow-up of the gonado and hepato somatic indexes: a spring period from April to June with a peak in May and an autumnal period, between November and January with a peak in December. The closed season in Oran Bay extends from 1 st May to 31 th August, which is to our opinion insufficient to safeguard the renewal of the resource and its spawning stock.
... This species represents a significant part of the fish fauna (40-70% in biomass) (Francour, 1997;. In the last 15 years, this poorly studied species in the Mediterranean sea has attracted research interest because of first, its role as macro-grazer of sea grass (Velimirov, 1984;Havelange et al., 1997;Jadot et al., 2000;Jadot et al., 2002), second, its biology in order to develop a management strategy (Méndez-Villamil et al., 2001;Méndez-Villamil et al., 2002), and finally for its toxicity. (Spanier, 1988;Spanier et al., 1989;Chevaldonne, 1990). ...
In this study we estimated by four appreciation methods the freshness state of Sarpa salpa species immediately captured. The TVB-N content is a tool of choice in the evaluation of fish species deterioration. The TBV-N content made possible to establish a narrow relation (R = 0.98) with the organoleptic examination (Freshness indexes). According to our results we suggest a value (28 mg N/100 g) as a limiting value of acceptance for the human consumption. Our results show that the bacterial development is the origin of the deterioration of freshness in the species studies, where Pseudomonas genus is the prevailing germ implied in the deterioration process. The storage time of Sarpa salpa should be limited to less than 6 days.
... This species represents a significant part of the fish fauna (40-70% in biomass) (Francour, 1997;. In the last 15 years, this poorly studied species in the Mediterranean sea has attracted research interest because of first, its role as macro-grazer of sea grass (Velimirov, 1984;Havelange et al., 1997;Jadot et al., 2000;Jadot et al., 2002), second, its biology in order to develop a management strategy (Méndez-Villamil et al., 2001;Méndez-Villamil et al., 2002), and finally for its toxicity. (Spanier, 1988;Spanier et al., 1989;Chevaldonne, 1990). ...
Rosemary (Rosmarinus Officinalis L.) leaves extracts showed a very high antioxidant activity and increasingly used as food additives and proposed as important human dietary factor. The oils’ antioxidant potential was determined by DPPH. assay and Trolox equivalent antioxidant capacity (TEAC) assay. Aqueous and Methanolic extracts were obtained and concentrated by nanofiltration and ultrafiltration using three kind of membranes in the aim to concentrate the retentate or the permeate in rosmarinic or carnosic acids. The essential oils analyzed by GC-MS technique showed the following fractions: 1,8-Cineole (44.86 %), Camphre (14.39 %), and α-pinène (12.62 %). The antioxidant effects, the levels of total phenol and the total phenolic contents of volatile oils and plant extracts were determined in various Rosmarinus Officinalis plants. Antioxidant activities and the total phenolic contents were measured by spectrophotometric method as well as the volatile oil content of the fresh plants with gas chromatograph. The results clearly indicated that the antioxidant capacity of volatile oils and plant extracts closely related to the total phenol contents. R officinalis L. essential oils and aqueous or methanolic extract and their permeate and retentate obtained using membrane technology showed interesting results, being one of the best performing in terms of ability to neutralize free radicals.
... Fish species belonging to the family Sparidae are widespread in the Mediterranean Sea and constitute an important fishery resource (Jardas, 1996). Results of previous studies indicate that the adult Sarpa salpa has rapid growth rates along the east coast of South Africa, with a maximum age of six years (van der Walt and Beckley, 1997), while off Canary Islands this species may reach a maximum age of eleven years (Méndez-Villamil et al., 2001). Several biological aspects of juvenile S. salpa have been studied and it has been shown that this species predominantly inhabits Posidonia oceanica beds (Harmelin-Vivien et al., 1995;Francour, 1997;Guidetti, 2000). ...
Growth of juvenile Sarpa salpa from the Kornati Archipelago, eastern middle Adriatic Sea was analysed. A total of 1515 juveniles, ranging in length from 1.6 to 14.2 cm, were caught. Most individuals (94.65%) belonged to the 0+ cohort. The first settlers were aged 1.5-2.0 months, and probably entered shallow coves at the end of November. The relationship between total length and weight indicates positive allometric growth (b = 3.284). The condition factor, as a consequence of length-weight relationship, was CF = 1.41. The parabolic (c = 0.023 mm days-1; R2
... Sarpa salpa lives in schools along the rock-bottomed coast. It is found in depths of 0-40 m (Verlaque, 1990;Mendez-Villamil, 2001). Its density has been estimated from 0.03 to 77.6 ind 10 m −2 (Francour, 1997;Harmelin-Vivien and Francour, 1997). ...
In the Mediterranean Sea, the fish Sarpa salpa (Sparidae) is the only vertebrate grazer of Posidonia oceanica meadows. In order to gain knowledge about the behaviour of S. salpa and a better understanding of the meadow's primary production recycling, an original study was designed using ultrasonic telemetry to investigate activity patterns and space utilisation in the field. During June-September 2000, we compared diel movements of six adult S. salpa (249-317 mm FL and 313-633 g) in the Bay of Calvi. These fish were tagged by intraperitoneal insertion of ultrasonic transmitters. Their positions were recorded with a directional hydrophone from a small boat with an accuracy between 10 and 50 m, depending on the local environment. The tracking duration ranged from 3 to 22 days (average 11.8 ± 7.3). Locations were performed from at least dawn to dusk or early night, and one fish was tracked during the entire 24-h cycle. Fish were more mobile during the twilight periods, but statistical analysis indicated individual differences for the precise period of mobility. Two major behavioural patterns were observed: first, the fish remained in close vicinity of the harbour during the day and moved away to the north or the south at dusk to access nocturnal sites, occupying a home range of about 4.3 ha. The second behavioural pattern involved persistent occupation of the same sites during day and night within a relatively restricted home range (about 0.8 ha). Great variation in mobility was found and the same individual fish could show both kinds of behaviour. © 2002 Ifremer/CNRS/Inra/IRD/Cemagref/Éditions scientifiques et médicales Elsevier SAS. All rights reserved.
... The salema, Sarpa salpa (L.), is an eurytherm species widely distributed throughout the Mediterranean, the whole Atlantic coast of Africa, including the Azores and Canary Islands, and also round South Africa to south of Mozambique on the Indian Ocean coast (Bauchot and Hureau, 1990). In the last 15 years, this poorly studied species in the Mediterranean Sea has attracted research interest because of first, its role as macro-grazer of seagrass (Velimirov, 1984;Havelange et al., 1997;Jadot et al., 2000Jadot et al., , 2002, second, its biology in order to develop a management strategy (Méndez-Villamil et al., 2001, and finally, its toxicity. Indeed it can cause Ciguatera-like or Caulerpa poisoning when consumed (Spanier, 1988;Spanier et al., 1989;Chevaldonne, 1990). ...
Acoustic telemetry was used to record diel movement and habitat utilization of the salema (Sarpa salpa) (Teleostei: Sparidae) during three consecutive summers from 2000 to 2002 in the Calvi and Achiarina bays of Corsica in the
Mediterranean Sea. A total of 18 fish was equipped with acoustic transmitters inserted in the body cavity, 13 were tracked
in the Bay of Calvi (275 mm ± 26.9 LF), and 5 in Achiarina Bay (260 mm ± 33.6 LF). Two different systems were used to track the fish. The one used in the Bay of Calvi was a manual receiver and a directional
hydrophone. The second system, used in Achiarina Bay, was a radio-acoustic-positioning (RAP) system that continuously monitored
the movements of the fish. Fish positions were put in a geographic information system (GIS) with information on the substratum
and depth. Two patterns of behaviour could be identified in the three years. Either the fish had clearly defined daytime as
opposed to night-time areas of residency, characterized by different depths and substrata or the fish persistently occupied
the same sites during both day and night. In the Bay of Calvi, six fish were released 1 km from the capture site. All of them
showed homing ability and returned to the site within 48 h.
In a marine ecosystem, the most sensitive organisms to environmental changes, mainly to anthropic pressures, are fishes and invertebrates. Therefore, they are considered the ideal targets to indirectly evaluate the health of an entire ecosystem. Teleost fishes, particularly those that occupy the highest trophic levels, can accumulate toxic substances through their diet. In this study, we used two fish species with sedentary behavior and trophic habits, Diplodus sargus and Sarpa salpa, caught in two areas at different anthropic pressures divided into the Gulf of Naples (Na) and the Gulf of Salerno (Sa). This study aimed to correlate the pathological alterations in target organs in both species with known concentrations of polychlorinated biphenyls (PCBs) and heavy metals (lead and cadmium) to the expression of CYP1A1. Histological examination took into consideration circulatory disorders, increase in melanomacrophages (MMs) number, inflammation in kidney and hepatopancreas and gonadal stage maturation. Next, the pathological and morphological changes found were compared to immunohistochemical expression of CYP1A1 in the same samples. Chemical analysis of PCBs, based on 28, 52, 101, 138, 153, and 180 congeners, and heavy metals, were performed on hepatopancreas and muscle samples. Higher median values of PCBs concentration were detected in both species in the Salerno area (8.1 ng/g in Diplodus sargus muscles and 51.1 ng/g in Sarpa salpa hepatopancreas, respectively), although the values were consistently below the legal limits. No critical values were found for lead and cadmium. Therefore, we hypothesized that CYP1A1 and pathological alterations were more expressed in fish from Salerno area. The pathological changes showed a statistically significant difference in inflammation of the kidneys (p < 0.0001) between S. salpa of both Gulfs. In addition, we found a statistically significant difference in the assessment of the increase in MMs/MMCs (p = 0.0384) and circulation disorders (p = 0.0325) of hepatopancreas in D. sargus of both Gulfs. As not all the variables considered showed statistical significance, the analysis of the results does not fully support the correlation between the highest levels of contaminants found in the Salerno area and the expression of CYP1A1. Our data could be a starting point for future studies to better correlate the role of CYP1A1 to pollutants, considering this is the first study involving two of the most common species in the Mediterranean Sea. Thus, future studies could include other species to improve and increase records.
In this study two hermaphrodite species samples of Bizerte sea.In order to compare the morphological variability (Fourier coefficients) and biometric charcaters (length, width, area and otolith perimeter). The result show a significant results that are clearly demonstrated by an asymmetry when comparing otoliths (P < 0.05) for S.scriba and for S.salpa showed a symmetry (P = 0.056).However for biometric comparison, between the rigth and left otoliths for each population, we detected a highly difference between otolith in all the parameter of S.salpa .
All these difference existing between the two species can be related to the environmental specificity and stress. In addition, asymmetry in width character is could be explained by the vulnerability of this trait to immediate changes in environmental factors.
This chapter comprehensively details Mediterranean lagoonal‐marine migratory fish Sparidae. It provides information regarding their systematics, ecobiology, ethology, genetics and their exploitation. Fish of the Sparidae family are characterized by a fairly compressed fusiform or oval body, their anterior profile being elevated by the existence of a supra‐occipital crest. Diplodus annularis belongs to the subfamily of Sparidae species. It is present in the Mediterranean, Black Sea and Azov Sea. The chapter presents the growth parameters of the Ludwig von Bertalanffy model obtained in different regions of the Mediterranean. Diplodus annularis feeds both during the day and at night. Diplodus puntazzo is found mainly in the Mediterranean and the eastern Atlantic, from the Bay of Biscay to Sierra Leone, the Canary Islands and Cape Verde. It belongs to nectobenthic species, and is therefore coastal and gregarious. Diplodus puntazzo is the subject of semi‐industrial, artisanal and recreational fishing.
Life-history traits of the sparid Boops boops are studied for the first time in an isolated Atlantic population. Boops boops is a hermaphrodite species characterised by late gonochorism or non-functional hermaphroditism. The 1:0.852 ratio of females to males was significantly different from unity. Both sexes had similar size distributions; however, females outnumbered males at sizes of between 16 and 18 cm TL, whereas males predominated among fish larger than 28 cm TL. The average lengths at first maturity for females and males were 16.02 (SD 0.28) and 16.49 (SD 0.25) cm TL, respectively, with no significant difference between sexes. Spawning-capable females were first observed in January, at a low percentage, and were present until May. The gonadosomatic index of both females and males peaked in February. Vitellogenesis did not begin synchronously, and the simultaneous presence of oocytes in all stages of development indicated an asynchronous mode of ovarian development. The presence of postovulatory follicles, together with tertiary-yolk-vesicle oocytes, indicates that the species is a multiple spawner. An age–length key showed an age-group composition for females of between 0 and 4 years, whereas males were between 0 and 5 years. The von Bertalanffy growth parameters for females were L∞ = 32.3 cm TL, k = 0.44 y–1 and t0 = −0.81 y, and for males they were L∞ = 35.3 cm TL, k = 0.38 y–1 and t0 = −0.80 y.
Growth of juvenile Sarpa salpa from the Kornati Archipelago, eastern middle Adriatic Sea was analysed. A total of 1515 juveniles, ranging in length from 1.6 to 14.2 cm, were caught. Most individuals (94.65%) belonged to the 0+ cohort. The first settlers were aged 1.5-2.0 months, and probably entered shallow coves at the end of November. The relationship between total length and weight indicates positive allometric growth (b = 3.284). The condition factor, as a consequence of length-weight relationship, was CF = 1.41. The parabolic (c = 0.023 mm days-1; R2 = 0.936) and Gompertz (c = 0.047 mm days-1; R2 = 0.897) growth models seem to be the most appropriate for the description of young S. salpa growth.
A member of the Sparidae family, the goldline sea bream Sarpa salpa (Linnaeus, 1758) collected from the Gulf of Tunis and the Bay of Bizerte in Northeast Tunisia, Western Mediterranean, were examined for the myxozoan parasites. During the parasitological exposure, a total of 7 myxosporean are found including 6 coelozoic species belong to the genus Ceratomyxa Thélohan, 1892 infected the gallbladder of their host of which 3 known species have been previously described, C. arcuata Thélohan, 1892, C. pallida Thélohan, 1895 and C. herouardi Georgévitch, 1916 and 3 species seem different in morphology to Ceratomyxa spp already known from Mediterranean Sea or from other localities in the wide world. These species are Ceratomyxa sp. 1, Ceratomyxa sp. 2 and Ceratomyxa sp. 3. Only one histozoic species belongs to the genus Henneguya Thélohan, 1892, Henneguya sp. identified for the first time infecting the mesentery vessels of S. salpa. The myxosporean parasite C. arcuata Thélohan, 1892 is reported for the first time in Tunisian waters from the goldline sea bream which represents as new host records. In addition to the Monoparasitism, the phenomenon of Polyparasitism was observed between the current species in both sampling sites with two types: Biparasitism and Triparasitism. The most frequent Polyparasitism was a Biparasitism-type between C. herouardi and C. pallida with frequency 16.97%. For all the species, no serious pathogenic changes have been recorded in the host organ or in the outward appearance of the fish. Morphological features, site of infection into the host, parasite prevalence and mean intensity of each myxosporean found during this survey are determined and their taxonomic affinities to other species are discussed.
The age and growth parameters of Diplodus puntazzo from the eastern middle Adriatic Sea were studied. Total lengths (TL) of 630 specimens ranging from 13.3 to 46.7 cm were obtained from commercial fishery catches by "tramata" fishing (2004-2005). All specimens sampled were fully mature above 22 cm TL. The male-female ratio for all fish combined was 0.75:1.00, but the ratio changed according to length classes. The mean lengths, as well as the age frequency distributions of males and females were not significantly different. Scales showed clearly the ring pattern common to teleost fishes. The opaque ring was deposited during the summer months. The length-weight relationship showed an isometric growth (b = 3.001; R2 = 0.988). The parameters of the von Bertalanffy growth equation were: L∞ = 45.28 cm; K = 0.191 per year; t0 = -0.306 year; R2 = 0.953. This study revealed that D. puntazzo is a relatively slow growing and long-lived species with a life span in excess of 18 years.
In the context of growing anthropogenic disturbances that deeply alter marine coastal ecosystems, various management tools are used to protect biodiversity, such as fishing gear limitations, fishing quotas, protected areas or the creation of artificial reefs (ARs). In contrast to the other management tools, ARs require a modification of natural habitats. We used under - water visual censuses to investigate the effect of habitat modification on the structure of fish communities by comparing a natural reef (NR) to ARs with different habitat complexity. Different fish assemblage descriptors were used to assess species- and functional- and community-level aspects of the assemblages. ARs were rapidly colonized by adult fishes and presented community compositions different from that of the NR. Fish densities and functional richness were higher in the ARs than in the NR. Small isolated artificial structures, such as culverts and box-culverts, had different fish community compositions than more extended and complex structures, demonstrating the effect of structural habitat complexity on fish assemblages. Fish density was higher in small structures, most likely due to habitat isolation and patchiness. This study indicates that ARs which are located along sandy coastal areas with few rocky habitats and under high river nutrient influence are a suitable habitat for rocky coastal fish communities. Nevertheless, due to higher habitat complexity and lower fishing pressure on ARs, fish communities of an AR functionally differ from those of a NR. Further research is necessary to understand how these differences act on the properties of the ecosystem as well as on local fisheries.
Salema Sarpa salpa (Linnaeus, 1758), were caught in the middle-eastern Adriatic Sea from August to November 2004. Length range of the samples was between 10.3 and 43.9 cm, with mean values of 25.5 cm in males, 32.6 cm in females, and 11.4 and 20.2cm in immature and hermaphrodite specimens, respectively. Sex ratio (males : females) was 3.1 : 1. Males were observed up to 37 cm length. Hermaphrodites showed lengths between 18 and 21 cm. The species was characterized by protandric hermaphroditism. Size at sexual maturity was 20.6 cm (2 years old) for males. Total length-total weight relationship for the entire population is described by the parameters a = 0.00893, and b = 3.1055. Otolith age readings showed that the population consisted of 15 age groups (1–15 years), including a very high proportion of individuals 1–7 years old. The von Bertalanffy growth parameters were L∞ = 33.11cm, k = 0.514, and t0 = −0.392 years for males and L∞ = 40.85cm, k = 0.179, and t0 = −2.606 years for females. Survival rate of females (S = 0.870) was much greater than for males (S = 0.769).
The reproductive biology of the sparid fish, Sarpa salpa, was investigated along the east coast of South Africa between January 1994 and March 1995. A protracted winter spawning season was identified, extending from April through to September, and it was evident that S. salpa migrate annually to KwaZulu-Natal from juvenile nursery areas in the Eastern and Western Cape. Size at 50% maturity for male S. salpa was attained at 145 mm fork length, while the adult sex ratio in the shore-based catch was 1:1.6 in favour of males. Frequency distribution by size indicated that males dominated the smaller size classes while females dominated the larger size classes. Histological examination of gonadal development revealed five types of gonads, namely undifferentiated, juvenile, male, intersex, and female gonads. Intersex gonads were characterised by degenerating testicular tissue separated from a dormant ovary by connective tissue. The population demography and the presence of intersexual individuals with degenerating testicular tissue was suggestive of protandrous sex change in S. salpa. This was confirmed during a captive study in which male S. salpa changed sex to female. Group spawning behaviour is postulated based on various morphological and indirect behavioural characteristics.
The age structure, growth and reproductive biology have been determined for the recreationally and commercially important King George whiting, Sillaginodes punctata, off southwestern Australia. The maximum lengths and ages, asymptotic lengths (L∞), and growth coefficients (K) were 596 mm, 14 years, 532 mm, and 0.47, respectively, for females, and 555 mm, 13 years, 500 mm and 0.53, respectively, for males. Sexual maturity is attained by 50% of female S. punctata by ca. 410 mm in length, and by the majority of both female and male fish at the end of their fourth year of life. The monthly trends in the proportions of mature gonads and the prevalence of different oocyte stages and postovulatory follicles indicated that, in southwestern Australia, S. punctata spawns from June to September. Spawning is thus initiated when water temperatures are declining from their maxima. During the spawning period, many of the ovaries of large fish contained yolk vesicle and yolk granule oocytes, as well as hydrated oocytes or postovulatory follicles (or both), indicating that S. punctata is a multiple spawner. Furthermore, because hydrated oocytes or postovulatory follicles were often found together with large numbers of yolk granule oocytes, S. punctata presumably releases eggs in batches during the spawning period. Recruitment of S. punctata into sheltered nearshore waters (<1.5 m) commences in late September, three months after the onset of spawning, and continues until early November. When juvenile S. punctata reach ca. 1.5 years of age and ca. 250 mm, the legal minimum length for capture, they move out into slightly deeper waters (2-6 m) in marine embayments and estuaries. After attaining ages of ca. 4 years and lengths of ca. 370 mm, they then migrate from these waters, where fishing pressure is greatest, into regions near or around reefs at depths of 6-50 m, where spawning occurs. In contrast to S. punctata, the five other whiting species in southwestern Australian waters, which all belong to the genus Sillago, spawn between late spring and early autumn. In the case of the three Sillago species that undergo an offshore migration, this movement occurs at a relatively small size and young age and leads to their occupying open sandy areas. The implications of S. punctata habitat and biological data for fishery management are discussed.
A total of 639 pink dentex Dentex gibbosus was collected in Canary Islands waters between April 1991 and September 1993. Total lengths ranged from 14,2 to 95,2 cm. Females dominated smaller size-classes and males the larger ones. The species was characterized by protogynous hermaphroditism. The overall ratio of males to females was 1 : 1,45. The reproductive period extended from April to September, spawning peaking in June/July. The total lengths at 50% maturity were 34,7 cm for females and 38,6 cm for males. The length-mass relationship for the whole sample can be described by the parameters a = 0,01014 and b = 3,0812. Fish aged 0–16 years were present in the samples. The parameters of the Von Bertalanffy growth equation were: L∞ = 101,2 cm, k = 0,149·year−1, and t0 = −0,111 years. The rates of total mortality Z and natural mortality M were 0,57 and 0,28·year−1 respectively. Rates of fishing mortality F and exploitation E were 0,29 and 0,51·year−1 respectively. The estimated length at first capture (LC50) was 17,8 cm total length.
Samples from sheltered nearshore waters in south-western Australia, in which Sillago schomburgkii spends its entire life cycle, have been used to determine the age structure, growth rate, age and length at first sexual maturity, and spawning period of this whiting species. Several S. schomburgkii reached four to seven years in age and one 12+ fish was caught. The respective maximum and asymptotic lengths (L∞) were 350 and 333 mm for females and 348 and 325 mm for males, while the growth coefficients (K) for females and males were 0.53 and 0.49, respectively. Sexual maturity was attained by both sexes of S. schomburgkii at ca. 200 mm, a length reached at the end of the second year of life. Monthly trends exhibited by gonadosomatic indices, the proportions of mature gonads and the prevalence of advanced oocytes and post-ovulatory follicles demonstrate that S. schomburgkii spawns predominantly from December to February. The presence of yolk vesicle and yolk granule oocytes and post-ovulatory follicles in the same ovaries during the spawning period, indicate that S. schomburgkii is a multiple spawner. The patterns of growth of the five Sillago species, that occur in south-western Australian marine waters, fall into two categories. The first, which consists of S. burrus and S. robusta, has a small L∞, i.e. 00 mm, and has a low K, i.e. ≤ 0.5. The lengths and ages at maturity of S. schomburgkii, S. bassensis, S. burrus and S. robusta, as well as of S. analis and S. flindersi found elsewhere in Australia, are linearly related to their asymptotic lengths and maximum ages, respectively. The two smallest species, S. burrus and S. robusta, attain maturity at ca. 130 mm. However, the former species, whose juveniles occupy productive nearshore waters, grows rapidly and reaches this length by the end of the first year of life, whereas the latter species, which is restricted to deeper waters, grows more slowly and thus does not attain this length until a year later. Sillagoflindersi, which is slightly larger than S. burrus and S. robusta, migrates out into deeper waters and attains maturity at ca. 170 mm and two years of age. Although S. schomburgkii, S. analis and S. bassensis attain maturity at ca. 200 mm and reach similar lengths, the first two of these species, which remain in nearshore waters and display more rapid growth, reach maturity one year earlier than the last species, which migrates out into deeper and presumably less productive waters. While S. vittata reaches a similar size and likewise migrates out into deep waters, it reaches maturity earlier, i.e. at the end of its first year of life.
The biology of the sparid fish, Pachymetopon grande, was investigated from data collected on the southeastern Cape coast between August 1984 and March 1987. Sectioned sagittal otoliths revealed that they are a slow-growing, long-lived species capable of reaching ages in excess of 40 years. Detailed histological examination of gonadal development showed that they are rudimentary hermaphrodites, males and females maturing after a non-functional intersexual stage. The breeding season is restricted to between January and June, and observations suggest that they are group spawners with pelagic eggs. Maturity was reached at 300 mm fork length or approximately 5,5 years old. P. grande is primarily herbivorous, feeding selectively on rhodophytes found on inshore reefs down to approximately 20 m. Minor dietary components included hydrozoans, octocorals and other small invertebrates. Macroalgal degradation by gut endosymbbnts or the utilization of macroalgal epibionts was not evident, suggesting that storage and extracellular carbohydrates of the macroalgae were utilized in the diet. The importance of P. grande to the inshore recreational angling fishery, together with certain aspects of its biology, underline the need for conservation measures aimed at ensuring the sustainability of this resource.