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Mar 2025 DOI 10.14302/issn.2637-6075.jpae-25-5464
R. Hodgson BruceCorresponding author
Antarctic krill is an important component of the zooplankton production in the Southern Ocean and is a major food source for baleen whales. The role of commercial fishing and predation by whales on Krill abundance has been investigated here using the innovative ecosystem-based fishery management, EBFM which maintains the krill to whale food web ecosystem stability. The literature indicates the Krill fishery may have been overfished, so it was reduced to the current annual upper limit of 0.62 million tonnes for support other predators of krill, such as seals, penguins and flying sea birds. However, recent literature suggests a moderate reduction in krill catch in the Antarctic Peninsula area due to its importance for whale migration to temperate areas. The Peninsula area catch was estimated to be reduced by about 10% due to additional concerns about climate change effects on krill abundance in the Southern Ocean, reducing overall catch to 0.556 million tonnes, moderately higher than the maximum taken in 2022. Hence, the krill biomass fishing was reduced to allow for predation by baleen whales and other predators, giving a full ecosystem-based fishing mortality similar to that previously estimated to maintain krill production in the Southern Ocean.
Jul 2025 DOI 10.14302/issn.2643-0282.imsj-25-5590
R. Hodgson BruceCorresponding author
The main diet of baleen whales is krill in the Arctic, Antarctic and during migrations in the Atlantic, Pacific and Indian Oceans. Hence, the aim of this paper is to quantify the global importance of the krill to baleen whale component of the pelagic food web and possible feedback loops. That was undertaken by comparing the results of Ecopath Models in the Antarctic and Arctic Oceans and to migration areas in the North Atlantic and Alaska, was well as the large Seamount area from the Antarctic and Arctic. Biological production transfer is the essential component of the prey to predator pelagic food web, which maintains the production of predators. The importance of sustaining global baleen whale migrations is to support ecosystem production by whale defecation contribution to nutrient recycling. It is important to sustain krill and fish abundance in whale migration feeding areas using ecosystem-based fishery management (EBFM) fishing rates. It was shown by the literature that migrations tended to followed deep-sea seamounts, and baleen whale defecation and nutrient cycling at seamounts led to the effects of nutrient upwelling by deep sea currents at seamounts. Hence, it is suggested seamounts be protected as important marine ecosystems. Therefore, those processes indicate sustaining krill and whale abundance is likely to support global marine ecosystem stability in open ocean migration areas.
Jul 2019 DOI 10.14302/issn.2691-6622.ijar-19-2762
MIÉGOUÉ EmileCorresponding author
University of Dschang, Faculty of Agronomy and Agricultural Sciences, Department of Animal Production, Animal Nutrition and production Research Unit
This study was conducted within three months at the University of Dschang Research and Application Farm (5°44’-5°36’ et 5°44’-5°37’ LN ; 10°06’-9°94’ et 10°06’-9°85’ LE). The main objective was to evaluate the integration perspectives of caviaculture and fishery. Specifically, the study was aimed at evaluating the production of guinea pig dungs, its bromatological composition and appreciating the nitrogen/phosphorus ratio in other to determine the adequate quantities of manure for a proper fertilization of fish ponds. Hence, 96 guinea pigs weighing averagely 390 ± 110g each were randomly distributed into two comparable lots (floor covered with litter and floor without litter) and were subjected to 8 feeds (5 grasses and 3 legumes). Each lot had 6 repetitions of 8 individuals. The animals were fed three times daily within 30 days. The dungs of guinea pigs were collected after three days between 6 and 8am during the experimental period. They were then selected and weighed using and electric balance of 0.1g sensitivity. At the end of the study, the following results were obtained: a guinea pig of 390 ± 110 g in confinement produced between 51.7 ± 0.4 to 60.5 ± 0.7g (fresh weight) of dung per day. The bromatological analysis of these dungs showed that they are made of organic material (80.0%), dry matter (94.3%), crude protein (10.7%), ash (19.9%) and nitrogen (22.7%). These results attesting the richness of these dungs helped in estimating the quantities (103.4g to 206.8g) of dung/day/100m2 for the breeding of 2 to 4 guinea pigs per fish pond of 100 m2 for an integrated breeding (guinea pig-fish).