Preliminary report of fishing at the Alawariwa beels, Ogun State, Nigeria

The Alawariwa beels located in the flood plains of the Ogun River, off Ibafo in Owode/Obafemi Local Government Area of Ogun State number 16 with an approximate total surface area of 28.0 hectares. The beels are conveniently exploited between January and April annually when the dry season and riverine contraction make this possible. The daily landing showed that the fish enclosure is truly a natural fisheries reserve as well as a medium of biodiversity. Fish catch per unit effort is reasonable especially for the more abundant fish species. The beel is sufficiently productive and worthy of the fishing efforts of the fishing efforts of eight fishers undertaking the daily assignment. Beel fishing is therefore economically advisable for fishers having access to such valuable communal or individual natural wetland resources

Management of fishing capacity in a spiny lobster (Panulirus argus) fishery: analysis of trap performance under the Florida spiny lobster Trap Certificate Program

The spiny lobster (Panulirus argus) fishery in Florida was operationally inefficient and overcapitalized throughout the 1980s. The Trap Certificate Program initiated during the 1992–93 season was intended to increase gear efficiency by reducing the number of traps being used while maintaining the same catch level in the fishery. A depletion model was used to estimate trap fishing efficiency. The costs of fishing operations and the value of the catch were used to determine the revenues generated by the fishery under different trap levels. A negative functional relationship was found between the catchability coefficient and the number of traps, which indicated that the fewer traps operating under the trap reduction scheme were more efficient. Also, the financial analyses indicated that the higher catch efficiency resulting from fewer traps generated significantly higher revenues, despite lower stock abundances. This study indicates that the trap reduction program had improved a situation that would have been much worse.

The vulnerability of reproductively active squaretail coralgrouper (Plectropomus areolatus) to fishing

Squaretail coralgrouper (Plectropomus areolatus) were captured and tagged at a fish spawning aggregation (FSA) site with conventional and acoustic tags to assess their vulnerability to fishing and spatial dynamics during reproductive periods. Males outnumbered females in catch and, on average, were larger than females. Findings revealed a high vulnerability to fishing, particularly during reproductive periods, and most fish were recaptured within the 5-month spawning season and within 10−12 km of the aggregation site. Individual and sex-specific variability in movement to, and residency times at, the FSA site indicates that individual monthly spawning aggregations represent subsets of the total reproductive population. Some individuals appeared to move along a common migratory corridor to reach the FSA site. Sex-specific behavioral differences, particularly longer residency times, appear to increase the vulnerability of reproductively active males to fishing, particularly within a FSA, which could reduce reproductive output. Both fishery-dependent and fishery-independent data indicate that only males were present within the first month of aggregation. The combined results indicate that reproductively active P. areolatus are highly vulnerable to fishing and that FSAs and migratory corridors of reproductively active fish should be incorporated into marine protected areas. The capture of P. areolatus during reproductive periods should be restricted as part of a comprehensive management strateg

Soft Flesh in Sablefish, Anoplopoma fimbria, of Southeastern Alaska: Relationships with Depth, Season, and Biochemistry

The condition of soft-textured flesh in commercially harvested sablefish, Anoplopoma fimbria, from southeastern Alaska was investigated by National Marine Fisheries Service (NMFS) scientists from the Alaska Fisheries Science Center’s Auke Bay Laboratories (ABL) in Alaska and the Northwest Fisheries Science Center in Seattle, Wash. Sablefish were sampled by longline, pot, and trawl at five sites around Chichagof Island at depths of 259–988 m in the summer of 1985 and at depths of 259–913 m in the winter of 1986. At the time of capture and data collection, sablefish were categorized as being “firm” or “soft” by visual and tactile examination, individually weighed, measured for length, and sexed. Subsamples of the fish were analyzed and linear regressions and analyses of variance were performed on both the summer (n = 242) and winter (n = 439) data for combinations of chemical and physical analyses, depth of capture, weight vs. length, flesh condition, gonad condition, and sex. We successfully identified and selected sablefish with firm- and soft-textured flesh by tactile and visual methods. Abundance of firm fish in catches varied by season: 67% in winter and 40% in summer. Winter catches may give a higher yield than summer catches. Abundance of firm fish catches also varied with depth. Firm fish were routinely found shallower than soft fish. The highest percentage of firm fish were found at depths less than 365 m in summer and at 365–730 m in winter, whereas soft fish were usually more abundant at depths greater than 731 m. Catches of firm fish declined with increasing depth. More than 80% of the fish caught during winter at depths between 365 and 730 m had firm flesh, but this declined to 48% at these depths in summer. Longlines and pots caught similar proportions of firm and soft fish with both gears catching more firm than soft fish. Trawls caught a higher proportion of soft fish compared to longlines and pots in winter. Chemical composition of “firm” and “soft” fish differed. On average “soft” fish had 14% less protein, 12% more lipid, and 3% less ash than firm fish. Cooked yields from sablefish with soft-textured flesh were 31% less than cooked yields from firm fish. Sablefish flesh quality (firmness) related significantly to the biochemistry of white muscle with respect to 11 variables. Summer fish of all flesh conditions averaged 6% heavier than winter fish. Regulating depth of fishing could increase the yield from catches, but the feasibility and benefits from this action will require further evaluation and study. Results of this study provide a basis for reducing the harvest of sablefish with soft flesh and may stimulate further research into the cause and effect relationship of the sablefish soft-flesh phenomenon.

A study of the crab pot as a fishing gear

The crab pot as a fishing gear was introduced in Maryland waters, following some years of greatly expanded use in Virginia, during the 1939 season, and was widely used during 1940. The 1941 session of the Maryland Legislature, however, illegalized the crab pot. Since that time the device has been given up almost entirely by Maryland fishermen, its attempted use in a commercial way having persisted in diminishing numbers in only one region of the state.

Trends in development in the prawn fishing technique in India: a review

The paper provides some background information about the developments in the prawn fishing technique. The important indigenous gear for prawns are the filtering type nets like the stake nets, boat seines and beach seines with bag. The only indigenous net, which can be compared in design with the modern bottom trawling gear, is the "Thuri Valai" of the Madras Coast. Prawns have also been reported from the catches of gill nets and cast nets. Dredges and beam trawls are simplest among the dragged gear. Even though several earlier attempts were made with the beam trawl, in 1959 season a detailed experiment was made to study the fishing features of this gear. The subsequent experiments conducted were for comparison with otter trawl, towing of 2 beam trawls one behind the other and the use of tickler chain. The initial experiments with otter trawls were mainly directed towards operational aspects. The experiments were to evaluate the effectiveness of fully mechanised and partially mechanised operation, the effect of extra buoyancy of floats and the use of tickler chain. Subsequent developments had been on the structure and design of prawn trawling gear. Effect of long wings and sweeps were tested. Catches of nylon and cotton nets were compared. The sizes of meshes of the cod-end have also been increased.

Penaeus indicus H. Milne Edwards, 1837: a summary of the conclusions from the fishing exploratory surveys between 1979 and 1837 at Sofala Bank, Mozambique

From 1979 to 1983, several surveys were carried out with research and fishing vessels at Sofala Bank in Mozambique. Their main objective was the assessment of shallow water prawn stocks, as this resource is of great economic importance for the country. A summary of the conclusions of these surveys regarding the species Penaeus indicus is presented. During the rainy season the species occurs closer to the shore than during the dry season. Estimates of biomass are very variable. The spawning peak seems to occur at the beginning of the rainy season (September-October). The spawning areas are located very close to the shore in the northern part of Sofala Bank and South of 17 degree 10'S in the 15-25 m depth interval.

The fishing centres of Lake Niassa (Mozambique): results of a frame survey made in June 1983

Results of the first frame survey of the fishing centres on the Mozambican coast of Lake Niassa, held in June 1983, are presented. A total of 41 fishing centres were detected in the area and visited. Through direct enquiries in each centre, an estimated number of 3,380 fishermen and 1,230 fishing boats (of which 25 motorized) was established. The results also provided information on the types and quantities of fishing gear used. A first estimation of the approximate total annual catch in the area gave a figure in the order of 9,100 tons., of which approximately equals 90% is landed during the rainy season. The survey is a part of a research programme on the fishing resources of Lake Niassa and of a project for the collection and organization of fisheries statistics from the artisanal fisheries of the Mozambican side of Lake Niassa.

Challenges to effective fishing and preferred fishing gear in a hydrodynamic freshwater system

Challenges to fishing and preferred gear of multiple used Lake, whose water depth is controlled by opening of its dam gate were investigated. Geographic survey, interview and focused group discussion of fishermen were used to assess factors influencing effectiveness of fishing and the preferred gear of Asejire Lake. Water usage (s) such as frequency of Complete and Partial Opening of Dams Gate (CODG and PODG) were investigated as indices for hydrodynamic condition. Response during focused group discussion with about 33% of fishermen of the Lake were obtained on sources of disturbance to effective fishing (SDEF), most effective gear (MEG)- least environmentally perturbed gear, comparability of catch structure of preferred gear to conventional gear and sustainability of superiority of preferred gears in situations outside hydrodynamic condition (SSPPG). The PODG occurred 1-7times/Month-dry season, 15-18times/Month-wet season; CODG occurred 1-2times/Month in both season; Interval of CODG was 3-17 and 5-12days (dry and wet season). It affected set-net and catch. The SDEF were gear availability, weather condition, dam’s gate opening, religion activities and Health of fisher-folks. 50% respondents accepted opening of dams gate as most important disturbance while religion was least (5% respondents accepted). 60% respondents accepted traps as MEG being the least affected while 75% respondents accepted Gura cage trap as the MEG among traps.90% respondents accepted that among traps, its catch structure was closest (comparable) to conventional gear. However, 75% respondents rejected SSPPG. Opening of dams’ gate creates hydrodynamic condition and it affects fishing. Gura trap was preferred for fishing hydrodynamic condition.

Monsoon trawl ban and its effects on the livelihood of trawl labourers: the case with Versova fishing village in Maharashtra

Indian fisheries sector in view of its potential contribution to national income, nutritional security, employment opportunities, social objectives and export earnings, plays an important role in the socio-economic development of the country. Fisheries sector contributes 4.3% to the agricultural GDP and export earnings are presently valued at over INR 68 billion from a volume of 460,000 tons. In addition, it provides direct and indirect employment and dependency for over seven million people in the country. With an estimated production potential of 8.4 million tons, the present level of production in the country is 5.9 million tons with almost equal contribution from both marine and inland sectors. The estimated fisheries potential from the Indian exclusive economic zone was found to be 3.9 million tons. But in spite of the increased efforts in fish production, the catch stagnates around 2.9 million tons. The stagnation in catches, mainly due to the over exploitation of dwindling marine resources, forced the government to impart some management measures to regulate the fishery and for the sustenance of the marine resources. The monsoon trawl ban in fisheries was one of the major reforms, which had created a substantial increase in fish production in the past few years. The ban on trawling during monsoon season was introduced in Maharashtra, after a series of studies, from 1992 for a period of 65 days from 10 June to 15 August or Naralipoornima, whichever is earlier. A notable increase in production from the marine sector of the country occurred in the post-ban period. Nevertheless, it had created problems in employment, poverty and income distribution of fishermen during the ban period and was always a matter of unrest between mechanized and traditional sectors of fishing. The aim of this study was to understand the impact of the ban on monsoon trawling in employment pattern, poverty and income distribution of fishermen along the coast of Maharashtra. The study was conducted at the Versova fishing village, Mumbai, and provides reflections on the possible impact of monsoon ban in the livelihood and standard of living of the fishermen in the state.

Assessment of impact of ten days fishing ban in the major spawning grounds of hilsa (Tenualosa ilisha, Fisher and Bianchi, 1984)

A study was undertaken to find out the impact of ten days fishing ban in the major spawning grounds of hilsa during October to December. The study revealed a positive impact of fishing ban during spawning season on reproduction success of hilsa. Proportionate distribution of male and female hilsa also showed a significant level of distribution in and around the spawning grounds where the ratio was 35:65. Percent of oozing hilsa during fishing ban period in the spawning grounds was observed 1.61%. About 5% spent hilsa was observed in the fish landing centers and was compared with the data of Global Environment Facility (GEF) and Bangladesh Fisheries Research Institute (BFRI) studies and was found about 2.80-3.57 times higher than that of the findings of 2002 and 2003. Estimated egg production value showed about 46,800 Kg of eggs could have been produced that indicating a positive impact of 10 days fishing ban in spawning season. Abundance of higher percentages of gravid hilsa was found which were not available in the same quantity and condition in the non-fishing ban period. During the present investigation, fairly higher amount of spent hilsa and juveniles were also observed in the spawning grounds. Along with the jatka fry, spawn and fries of other fishes were also found in higher quantity than the previous years and thus it is assumed that fishing ban also might have positive impact on the successful breeding of other fishes. Overall, the fishing ban was found effective for successful breeding of hilsa.

A description of certain indigenous fishing methods from Southern Dahomey

A survey of certain Dahomean fishing methods showed them to be specifically adapted to the exploitation of floodplains and shallow water lagoons. Several types of fish-parks are described, ranging from small installations thaI funclion as refuge traps, to larger constructions that act as a form of fish culture. Ponds are also dug in the floodplains in order to conserve fish isolated during the dry season. These methods all give high yields and are worthy of consideration for use elsewhere on the African continent.

Angling sport fishing in Lobo-Broa reservoir (Itirapina, SP, Brazil)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relative growth, sexual maturity, and breeding season of three species of the genus Persephona (Decapoda: Brachyura: Leucosiidae): A comparative study

The relative growths of Persephona lichtensteinii, P. mediterranea, and P. punctata were investigated on the south-eastern Brazilian coast, focusing on differences in the growth rates between immature and mature phases, the onset of morphological sexual maturity, and the breeding seasons of these species. Crabs were collected every two months from January 1991 through to November 1992, from a shrimp fishing boat equipped with two otter-trawl nets. Significant differences in the patterns of body growth were observed between immature and mature phases of all three species. Changes in the growth rates of the chelipeds (males) and abdomen (females) observed for P. lichtensteinii, P. mediterranea, and P. punctata, seem to be related to the puberty moult for both sexes. Males of P. mediterranea and P. punctata reached larger mean sizes of carapace width than females, whereas no difference was recorded for P. lichtensteinii. The body size at which 50% of males attained sexual maturity was also larger in P. mediterranea and P. punctata, and smaller in P. lichtensteinii. The absence of a pronounced sexual dimorphism and the size at the onset of sexual maturity observed only for P. lichtensteinii might be explained by distinct reproductive strategies of males. The presence of ovigerous females during the entire sampling period suggests that all three species have a continuous reproduction pattern at the Ubatuba region. Future studies on the population structure, functional maturity, and mating system should improve the understanding of factors driving the biology and ecology of these species at a subtropical region. © Marine Biological Association of the United Kingdom 2013.

Fishing effort and the impact of fishing gears and fishing methods on fishes and fisheries of Kyoga basin lakes

Lake Kyoga at the time of Worthington Survey (Worthington, 1929) was fished by only natives around it. The fishing gears consisted of locally made basket traps, hooks and seine nets made out of papyrus. Fishing was mainly during the dry season as in wet season, the fishers would revert to crop growing. During 1937 to 1950s Oreochromis variabilis, oreochromis esculentus (Ngege) and Protopterus aethiopicus (Mamba) were the most important commercial fish species and contributed over 95% to the total landings until early 1950s when their proportions started to change as a result of changes in fishing techniques. The tilapiines' were then being caught using mainly basket traps and P.aethiopicus was caught in hooks prior to the mid 1950s.