Catch Composition on Red Shrimps’ (Aristaeomorpha foliacea and Aristeus antennatus) Grounds in the Eastern Ionian Sea

In the present study, the catch composition and the catch per unit effort (CPUE) by weight and numbers in red shrimps’ (Aristaeomorpha foliacea and Aristeus antennatus) grounds was examined in the southern part of the eastern Ionian Sea, in order to collect important information for the Greek waters, where no deep-water fishery exists. In the depth stratum 500–700 m, the catch of the commercial species represented a high proportion (>70%) of the total catch. Red shrimps and several other commercial species were found in important quantities. The present results suggest the possibility of developing a deep-water fishery in Greece. In such a case, attention should be paid because of the high vulnerability of A. foliacea – the main deep-water fishing resource in the area – to the fishing pressure.     

Significance of new records of Tridacna squamosa Lamarck, 1819, in the Tuamotu and Gambier Archipelagos (French Polynesia)

The giant clam subfamily Tridacninae (family Cardiidae) is an important group of bivalve molluscs found throughout the Red Sea and Indo-Pacific, from East Africa to the Eastern Pacific biogeographic region. The Tridacna genus is currently revised with numerous cryptic species identified with molecular markers. New Tridacna records from the fringe of the known distribution areas are extremely useful to identify genetically unique species, geographic ranges, and to examine processes associated with species differentiation. While Tridacna maxima is abundant in French Polynesia (Central South Pacific Ocean) the larger fluted giant clam Tridacna squamosa was formerly reported only in the Austral Islands in the south. Following a recent survey that spanned 23 islands and atolls of the Society, Tuamotu and Gambier Archipelagos, the presence of T. squamosa between the Cook Islands and Pitcairn Islands is confirmed using both morphological and molecular information, suggesting a relic distribution across the Central Pacific Ocean. Tridacna squamosa is rare, but present throughout Tuamotu and Gambier. However, it remained undetected from the Society Islands, probably due to historical over-fishing. This species is valued by local inhabitants, and is sought after mainly as gifts and also for a limited local shell trade. The rarity of T. squamosa may call for conservation measures in the near future.     

The ecology of the fishes in Nyumba ya Mungu reservoir, Tanzania

Twenty species of fish were found in Nyumba ya Mungu reservoir on the River Pangani which, with two exceptions, were indigenous to the river basin. Their distribution is described and some information on their growth, reproduction and feeding habits is presented. The highest densities of fish were found in the littoral and the broad, shallow, upstream region of the lake. The lacustrine environment has favoured the endemic tilapias, Sarotherodon jipe and S. pangani , which graze periphyton, and the introduced species, S. esculentus which feeds on phytoplankton. Males of the endemic forms may grow to a large size, but the introduced species, including Tilapia rendalli , were heavier for a given length. A reduction in tilapia stocks since 1970 is reflected in experimental catches during 1972-74 and was attributed to the combined effects of heavy commercial exploitation and a loss of spawning grounds. In the same period a striking increase in the populations of small carnivores, Rhabdalestes leleupi and Haplochromis gr. bloyeti , was recorded. Kully plantivorous and piscivorous fish are absent but omnivores are represented by Barbus species and Synodontis punctulatus. Tilapias exhibited a high incidence of nematode infection and the available evidence indicates that fish-eating birds are important predators of cichlids in Nyumba ya Mungu.     

Size-spectra as indicators of the effects of fishing on coral reef fish assemblages

The data requirements and resources needed to develop multispecies indicators of fishing impacts are often lacking and this is particularly true for coral reef fisheries. Size-spectra, relationships between abundance and body-size class, regardless of taxonomy, can be calculated from simple sizeabundance data. Both the slope and the mid-point height of the relationship can be compared at different fishing intensities. Here, we develop size-spectra for reef fish assemblages using body size- abundance data collected by underwater visual census in each of ten fishing grounds across a known gradient of fishing intensity in the Kadavu Island group, Fiji. Slopes of the size-spectra became steeper (F_9,69=3.20, p<0.01) and the height declined (F_9,69=15.78, p<0.001) with increasing fishing intensity. Regressions of numbers of individuals per size class across grounds were negative for all size classes, although the slope was almost zero for the smallest size class. Response to exploitation of each size class category was greatest for larger fish. Steepening of the slope with increasing fishing intensity largely resulted from reductions in the relative abundance of large fish and not from the ecological release of small fish following depletion of their predators. The slope and height of the size-spectrum appear to be good indicators of fishing effects on reef fish assemblages.     

Microsatellite DNA markers for the study of Atlantic salmon (Salmo salar) kinship,population structure,and mixed‐fishery analyses

Eleven microsatellite DNA loci were identified and characterized for Atlantic salmon (Salmo salar) collected from the Penobscot River, Maine, USA and the River Nith, Scotland, UK. The markers revealed high levels of genetic diversity (seven to 48 alleles per locus), heterozygosity (to 100%), and allelic heterogeneity (all comparisons). Considerable differentiation was observed as the genetic distance (chord) between the two collections was 0.680 and the pairwise F_ST, 0.12, was highly significant. These findings are consistent with patterns of continental‐level differentiation observed previously using an alternate suite of microsatellite loci. Locus‐by‐locus analyses of molecular variance suggested that most markers were suitable for delineating kinships and population genetic structure.     

Fishery of the Deep-water Rose Shrimp Parapenaeus longirostris (Lucas, 1846) (Crustacea: Decapoda) in the Northern Tyrrhenian Sea (Western Mediterranean)

The aim of this study is to provide information on the fishing pattern of Parapenaeus longirostris in the northern Tyrrhenian Sea (western Mediterranean), in order to improve the management of the resource in the area. Data were obtained from commercial fishery, covering the period 1991–2002. Catch rates revealed notable inter-annual fluctuation of the P. longirostris landing, probably due to the life cycle of the species. The highest yields (kg per hour of trawl) of the commercial fishery were obtained at depths ranging between 180 and 300 m, the lower ones at depths between 100 and 180 m, where small specimens are more abundant. Commercial catches were characterised by a very low presence of specimens smaller than 20 mm carapace length (CL), mainly due to the deeper localisation of the fishing grounds when compared to the recruitment areas of the species. The size at which 50% of the specimens were discarded by the fishermen was 15 mm CL, while the estimated size at first capture of the individuals caught by the commercial net was 12.4 mm CL.     

The cost to government of maintaining a commercially unviable fishery: The case of newfoundland 1981/82 to 1990/91

The commercial fishery for northern cod off Newfoundland has been closed since 1992. Since then, the recreational “food fishery”; has also been closed, as have the fisheries for many additional cod and other groundfish stocks. The Newfoundland fisheries had been commercially unviable for many years before the closures. This article records the federal and provincial governments’ financial outlays (expenditures, transfer payments to individuals, subsidies, net equity purchases, and net loans) on the fishery during the decade following 1981. Special emphasis is placed on the cost of the financial restructuring of the industry in the mid‐1980s, net unemployment insurance payments, and social overhead capital expenditures.     

The politics of a new legal order for fisheries

Illegal, unreported, and unregulated (IUU) Fishing is considered a major threat to high seas fish stocks. Each of the the international regional fishery management organizations (RFMOs) are combating some form of IUU fishing and this led the Food and Agriculture Oranization of the United Nations (FAO) to adopt the International Plan of Action to Deter, Prevent and Eliminate IUU Fishing (IPOA-IUU). This article will analyze the issues involved with IUU fishing, examine the recommendations in the IPOA, and consider examples of successful management and enforcement measures in use by states and RFMOs. Finally, recent developments in China will be viewed as an example of how international cooperation is contagious.