Kabeljaukrise in der Nordsee erfordert neue bestandserhaltende Maßnahmen

The European Commission has claimed a fundamental revision of the European Common Fisheries Policy in its Green Paper (EC 2001) by highlighting the reasons of continued overfishing of a number of valuable demersal fish stocks. Quotas in excess of scientific recommendations, fleet over capacities and poor enforcement of management decisions were identified causal for major stock and yield reductions while gaps in scientific advices were also criticized. The depleted cod stock in the North Sea, Skagerrak and Eastern Channel is the most prominent example. Existing and proposed management regulations were analysed by an expert group which met with fishing industry consultations in Brussels during 28 April – 7 May 2003. Depending on compliance with new technical regulations since 2000, the cod stock and its exploitation was found only marginally effected, while whiting displayed immediately significant losses in yield over long term and short term losses in haddock yields were reversed in substantial gains, also in SSB. However, reduction in fishing effort was found more effective in recovery potential than technical changes including closed areas, for which detailed information about variation in distribution of the stocks and the fisheries are required. Such effort reductions would reduce not only landings but also unregulated discarding, which is believed to be a major reason of the failure of the management measures in mixed fisheries. Recent trends in fishing effort of European fleets could not be quantified due to persistent data deficiencies.

Green Guide to the Cayman Islands 1: The marine environment

In the Cayman Islands we are enriched with a wonderful natural environment. In this Green Guide to our Marine Environment we hope to show you how all of our lives on these three magical islands are intimately connected to the land and the sea that surrounds it. Like many of our Caribbean neighbours, a large proportion of our economy depends on reef-based fishing, diving and tourism. The beauty of our coral reefs, our beaches and our lagoons is that it is part of our heritage, and it draws many thousands of overseas visitors to our shores. It is our responsibility, as stakeholders sharing this beautiful environment, to do what we can to minimise our impact upon it. Ogier has sponsored the Green Guide, and through this publication, is helping us to preserve our natural and cultural heritage.... [PDF contains 32 pages]

Eggs, Larvae and Young of The Striped Bass, Roccus saxatilis

Detailed descriptions of the early development of the striped bass, Roccus saxitilis (Walbaum), with emphasis on variation in size and morphology, sequence of fin formation, changes in body form, and attainment of the full complement of maristic numbers, are presented and illustrated for the first time. The egg is spherical, transparent, non-adhesive and relatively large. It is pelagic and buoyant, although it sinks in quiet fresh water. When unfertilized, it averages 1.3 mm, in diameter, but is 3.4 mm. when fertilized and water-hardened. The granular yolk sac, green when alive and whitish-yellow when preserved, averages 1.2 mm., and the single amber-colored oil globule is about 0.6 mm. in diameter. Newly hatched striped bass prolarvae, which range from 2.9-3.7 mm. in total length, are relatively undeveloped and nearly transparent, with no mouth opening, unpigmented eyes, and a greatly enlarged yolk sac with the large oil globule projecting beyond the head. When 5-6 mm. long the yolk sac and oil globule are assimilated and the postlarvae I show advanced development of the internal anatomy. Although the fish is still transparent, scattered melanophores are found on the head and body and chromatophores in the eyes and the ventro-posterior edge of the body. Postlarvae transform to young between 7 and 10 mm. in length when the finfolds are lost except in the dorsal, anal and caudal regions. The largest fish in this group possess a well-formed skeleton with a full complement of 25 vertebrae. Between 10 and 20 mm. in length all fish are fully transformed, muscular tissue renders most of the internal structure obscure, and the myotomes, which generally correspond in number with the vertebrae, are no longer visible. At fish lengths of 20-30 mm. scales are found on all specimens, and with the exception of the pectoral fin-rays, a full complement of meristic structures is present in all other fins. At this stage the body is pigmented uniformly with small spots. Linear regressions between several dependent variables and the , independent variable of standard length indicate that the rate of development of head, eye. and snout to anus lengths is proportional to the length of the larvae and young. Body depth and standard length are non-linear among newly-hatched larvae. Hatchery-reared striped bass demonstrated a slow rate of growth, and were regarded as "stunted," when compared to growth rates observed in another study and field collections. Observations were also made on abnormal eggs and teratological larvae and young. Blue-sac disease is tentatively identified and described for the first time in larvae and pugnosed larvae and young are also described for the first time in striped bass.

The regulators and the regulated: fisheries management, options and dynamics in Kenya's Lake Victoria fishery

The study divides the history of the fishery into five 'regulatory periods': the pre-colonial fishery (pre-1901), the colonial fishery (1901-1963), the post indipendence fishery (1963-1980), the Nile perch 'boom' years (1980-1989), and finally the fishery in the 1990's. Within each of these periods, the nature of and the relationship between, formal and informal regulations differs and changes with time. In the pre-colonial period, the outcome of formal and informal regulations largely sustained the fishery in a productive and species diverse state. However, at no time since then have formal regulations worked, with the result that the nature of production from the fishery changes over time and is dependent on a number of factors, amongst which the most important are effort level increases, technological introductions, species introductions, changes in regional and national job markets, the change from community-based controls to state-based controls within the fishery, and finally, considerable changes to the fish markets.

A nursery site of the Alaska skate (Bathyraja parmifera) in the eastern Bering Sea

A nursery site for the Alaska skate (Bathyraja parmifera) was sampled seasonally from June 2004 to July 2005. At the small nursery site (~2 km2), located in a highly productive area near the shelf-slope interface at the head of Bering Canyon in the eastern Bering Sea, reproductive males and females dominated the catch and neonate and juvenile skates were rare. Seasonal samples showed summertime (June and July) as the peak reproductive time in the nursery although some reproduction occurred throughout the year. Timeseries analysis of embryo length frequencies revealed that three cohorts were developing simultaneously and the period of embryonic development was estimated at 3.5 years and average embryo growth rate at 0.2 mm/day. Estimated egg case deposition occurred mainly during summertime and hatching occurred during winter months. Protracted hatching times may be common for oviparous elasmobranch species and may be directly correlated with ambient temperatures as evident from a meta-data analysis. Evidence indicates that the Alaska skate uses the eastern Bering Sea outer continental shelf region for reproduction and the middle and inner shelf regions as habitat for immature and subadults. Skate nurseries may be vulnerable to disturbances because they are located in highly productive areas and because embryos develop slowly.

Management of wetland resources in the lower Mekong Basin: issues and future directions

The Lower Mekong Basin has extensive wetlands and these are being threatened by numerous problems. Most of these problems are interdependent and interact with one another. The lack of an appropriate definition of wetlands applicable to the region, pervasive inefficiencies and chronic lack of funds among riparian governments, and the poor appreciation of the true economic importance of wetlands and its resources are among the most prominent. The current definition, based on the Convention on Wetlands (Ramsar, Iran, 1971), is too broad when compared to the understanding of wetlands as being swamps, marshes and the like, and was developed specifically for wetlands with international importance as waterfowl habitats. Furthermore, wetlands are composed of different types of resources, which require different modes of management. Often, institutional competition, overlapping mandates and sometimes jealousies occur between government departments when they try to assert their authority on a particular wetland resource and use, and put forward their development plans without considering how these may conflict with other wetlands uses. Finally, effective wetland management requires reliable statistics or information on rate of harvest of natural resources such as fish and others, fishing/harvesting methods over time in order to determine the level of exploitation, and the status of the natural resources. This information is needed to identify opportunities for expansion, to establish historical trends, and to determine when management interventions are necessary to protect the resources from being overused by other developments. In order to address these issues, ICLARM - The World Fish Center has launched a project, the aim of objectives of which are described in this paper.

Seasonal changes in growth of coho salmon (Oncorhynchus kisutch) off Oregon and Washington and concurrent changes in the spacing of scale circuli

In this study we present new information on seasonal variation in absolute growth rate in length of coho salmon (Oncorhynchus kisutch) in the ocean off Oregon and Washington, and relate these changes in growth rate to concurrent changes in the spacing of scale circuli. Average spacing of scale circuli and average rate of circulus formation were significantly and positively correlated with average growth rate among groups of juvenile and maturing coho salmon and thus could provide estimates of growth between age groups and seasons. Regression analyses indicated that the spacing of circuli was proportional to the scale growth rate raised to the 0.4−0.6 power. Seasonal changes in the spacing of scale circuli reflected seasonal changes in apparent growth rates of fish. Spacing of circuli at the scale margin was greatest during the spring and early summer, decreased during the summer, and was lowest in winter or early spring. Changes over time in length of fish caught during research cruises indicated that the average growth rate of juvenile coho salmon between June and September was about 1.3 mm/d and then decreased during the fall and winter to about 0.6 mm/d. Average growth rate of maturing fish was about 2 mm/d between May and June, then decreased to about 1 mm/d between June and September. Average apparent growth rates of groups of maturing coded-wire−tagged coho salmon caught in the ocean hook-and-line fisheries also decreased between June and September. Our results indicate that seasonal change in the spacing of scale circuli is a useful indicator of seasonal change in growth rate of coho salmon in the ocean.

U. S. Trade in Tuna for Canning, 1987

U.S. tuna fleet activity, canned tuna processing, ex-vessel, wholesale and retail prices and imports in 1987 are described and compared to their counterparts in previous years. Industry statistics gathered from government agencies and industry contacts are presented in 14 figures and 8 tables. In 1987, U.S. tuna fisheries delivered 253,136 short tons (tons) of tuna to U.S. canneries. Domestic deliveries of albacore (white-meat) tuna were 2,836 tons, down 20 percent from 1986 levels. Domestic deliveries of tropical (light-meat) tuna (bigeye, blackfin, bluefin, skipjack, and yellowfin) were 251,000 tons, up 12 percent. Contract prices for tuna delivered by U. S. vessels to U. S. canneries increased dramatically in 1987. Depending on the size of fish in the delivery, ex-vessel prices of white-meat tuna increased as much as 27 percent, and prices of light-meat tuna increased as much as 47 percent. U. S. cannery receipts of imported and domestically caught raw frozen tuna for canning totaled 532,704 tons in 1987, up 2 percent from 1986 levels. U.S. cannery receipts of white-meat tuna were 104,197 tons, down 10 percent from 1986. Imports made up 97 percent of the total cannery supply. Total 1987 U. S. cannery receipts of raw, frozen light meat tuna were 428,507 tons, up 5 percent from 1986 levels. Imports made up 41 percent of the total cannery supply. The 1987 U.S. pack of canned tuna was 33.6 million standard cases, up 3 percent from 1986. The pack of white-meat tuna was 7.2 million standard cases, down 11 percent from 1986; the pack of light-meat tuna was 26.4 million standard cases, up 7 percent. U. S. imports of canned tuna in 1987 were 10.8 million standard cases, down 11 percent from 1986 levels, the first time in recent years that imports have declined. Per capita consumption of canned tuna in the United States was 3.5 pounds in 1987, down slightly from 1986. The retail composite price was $2.26 per pound, unchanged from 1986.

Fish and habitat community assessments on North Carolina shipwrecks: potential sites for detecting climate change in the graveyard of the Atlantic

The Monitor National Marine Sanctuary (MNMS) was the nation’s first sanctuary, originally established in 1975 to protect the famous civil war ironclad shipwreck, the USS Monitor. Since 2008, sanctuary sponsored archeological research has branched out to include historically significant U-boats and World War II shipwrecks within the larger Graveyard of the Atlantic off the coast of North Carolina. These shipwrecks are not only important for their cultural value, but also as habitat for a wide diversity of fishes, invertebrates and algal species. Additionally, due to their unique location within an important area for biological productivity, the sanctuary and other culturally valuable shipwrecks within the Graveyard of the Atlantic are potential sites for examining community change. For this reason, from June 8-30, 2010, biological and ecological investigations were conducted at four World War II shipwrecks (Keshena, City of Atlanta, Dixie Arrow, EM Clark), as part of the MNMS 2010 Battle of the Atlantic (BOTA) research project. At each shipwreck site, fish community surveys were conducted and benthic photo-quadrats were collected to characterize the mobile conspicuous fish, smaller prey fish, and sessile invertebrate and algal communities. In addition, temperature sensors were placed at all four shipwrecks previously mentioned, as well as an additional shipwreck, the Manuela. The data, which establishes a baseline condition to use in future assessments, suggest strong differences in both the fish and benthic communities among the surveyed shipwrecks based on the oceanographic zone (depth). In order to establish these shipwrecks as sites for detecting community change it is suggested that a subset of locations across the shelf be selected and repeatedly sampled over time. In order to reduce variability within sites for both the benthic and fish communities, a significant number of surveys should be conducted at each location. This sampling strategy will account for the natural differences in community structure that exist across the shelf due to the oceanographic regime, and allow robust statistical analyses of community differences over time.

Fish lost at sea: the effect of soak time on pelagic longline catches

Our analyses of observer records reveal that abundance estimates are strongly influenced by the timing of longline operations in relation to dawn and dusk and soak time— the amount of time that baited hooks are available in the water. Catch data will underestimate the total mortality of several species because hooked animals are “lost at sea.” They fall off, are removed, or escape from the hook before the longline is retrieved. For example, longline segments with soak times of 20 hours were retrieved with fewer skipjack tuna and seabirds than segments with soak times of 5 hours. The mortality of some seabird species is up to 45% higher than previously estimated. The effects of soak time and timing vary considerably between species. Soak time and exposure to dusk periods have strong positive effects on the catch rates of many species. In particular, the catch rates of most shark and billfish species increase with soak time. At the end of longline retrieval, for example, expected catch rates for broadbill swordfish are four times those at the beginning of retrieval. Survival of the animal while it is hooked on the longline appears to be an important factor determining whether it is eventually brought on board the vessel. Catch rates of species that survive being hooked (e.g. blue shark) increase with soak time. In contrast, skipjack tuna and seabirds are usually dead at the time of retrieval. Their catch rates decline with time, perhaps because scavengers can easily remove hooked animals that are dead. The results of our study have important implications for fishery management and assessments that rely on longline catch data. A reduction in soak time since longlining commenced in the 1950s has introduced a systematic bias in estimates of mortality levels and abundance. The abundance of species like seabirds has been over-estimated in recent years. Simple modifications to procedures for data collection, such as recording the number of hooks retrieved without baits, would greatly improve mortality estimates.

Movements of bocaccio (Sebastes paucispinis) and greenspotted (S. chlorostictus) rockfishes in a Monterey submarine canyon: implications for the design of marine reserves

In August and September of 1997 and 1998, we used SCUBA techniques to surgically implant Vemco V16 series acoustic transmitters in 6 greenspotted rockfish (Sebastes chlorostictus) and 16 bocaccio (S. paucispinis) on the flank of Soquel Canyon in Monterey Bay, California. Fish were captured at depths of 100–200 m and reeled up to a depth of approximately 20 m, where a team of SCUBA divers anesthetized and surgically implanted acoustic transmitters in them. Tagged fish were released on the seafloor at the location of catch. An array of recording receivers on the seafloor enabled the tracking of horizontal and vertical fish movements for a three-month period. Greenspotted rockfish tagged in 1997 exhibited almost no vertical movement and showed limited horizontal movement. Two of these tagged fish spent more than 90% of the time in a 0.58-km2 area. Three other tagged greenspotted rockfish spent more than 60% of the time in a 1.6-km2 area but displayed frequent horizontal movements of at least 3 km. Bocaccio exhibited somewhat greater movements. Of the 16 bocaccio tagged in 1998, 10 spent less than 10% of the time in the approximately 12-km2 study area. One fish stayed in the study area for about 50% of the study time. Signals from the remaining 5 fish were recorded in the study area the entire time. Bocaccio frequently moved vertically 10–20 m and occasionally displayed vertical movements of 100 m or greater.

Induced breeding, embryonic and larval development in Heteropneustes fossilis (Bloch) in the agro-climatic conditions of Maharashtra

Heteropneustes fossilis was induced bred for the first time in the agro-climatic conditions of Maharashtra, India. The embryonic development was completed within 16-18h after fertilisation. Head and tail ends were distinguishable after 3h and 11-12 somites were visible after 6-7h. The eggs started hatching after 14h of incubation. Average hatching time was 16-18h at 26 degrees C. In first day old pro-larva, notochord was deflected upwards, eyes were darkly pigmented and alimentary canal appeared. In fourth day old post-larva intestinal coiling could be seen and yolk was absorbed. Aerial respiration started by 8th day. The 10 day old post-larva was free swimming and fed voraciously attaining a length of 20 mm in 30 days.

Recent advances and scope for sea farming in India

Although brackishwater prawn and fish culture was traditionally practiced for a long time in the country, efforts at sea farming are still in their infancy. During the past 15 years the Central Marine Fisheries Research Institute has developed various technologies for sea farming of mussels, pearl oysters, production of cultured pearls, edible oysters, clams, prawns, lobsters, seaweeds and more recently sea cucumbers and top shells. The paper outlines recent developments in these areas as well as in others like sea ranching of marine prawns and pearl oyster, and scope for enlarging sea farming activities including development of artificial reefs in India.

Successful inoculation of Artemia and production of cysts in the coastal saltpans of Bangladesh II

Bangladesh has no naturally occurring Artemia, and all the growing shrimp hatcheries of the country depend entirely on import of cysts from foreign countries. Following successful inoculation of Artemia and production of cysts for the first time in this country in a coastal saltpan (at Chanua, Banskhali) by the senior author (in 1989-90), a similar second attempt was made under this programme in a saltpan (1000 m super(2)) of Demoshia, Chakaria, Cox's Bazar, Bangladesh between January and April 1992. A total of 1639.9 g (dry weight) of cysts (i.e. 5.46 kg DW/ha/month) have been produced using the Red Jungle Brand, whereas the previous attempt obtained 517 g of cysts (i.e. 2.07 kg DW/ha/month) using the Great Salt Lake Brand.

Acyclic diterpene alcohols isolated from four algae of Bryopsidophyceae and their toxicity

Three new acylic diterpenoids belonging to the class of phytol series have been isolated. They were obtained from the ethyl acetate soluble fractions of four siphonaceous green seaweeds, Bryopsis pennata Lamour., Caulerpa taxifolia (Vahl) C. Ag., Codium decorticatum (Woodw.) Howe and Valoniopsis pachynema (Mart.) Børg., collected from Karachi coast of Pakistan. Structures of these compounds were elucidated with the help of spectroscopic methods and confirmed by comparison with the known compounds. Even the known compounds are being reported for the first time from a green algal source. All the compounds were found to display a strong toxicity at all the three concentrations tested in the brine shrimp bioassay.