Aquaculture Sustainability And Ecosystem Approach To Fisheries Management

The importance of maintaining sustainability in aquaculture

1 What is an “ecosystem” approach to fisheries management and where does aquaculture fit in?

2 “The only way to satisfy future demands for fish and shellfish will be through increasing aquaculture production”. Discuss.

3 Describe the recent advances and constraints of farming a named species. What are the future production prospects for this species?

4.“Lack of management, sparse biological data and low conservation priority are the biggest impairments to elasmobranch conservation”. Discuss this statement, supporting your arguments with examples.

5 Describe the principles of MSE full-feedback simulation, and explain what kind of insights can be derived from it, if necessary illustrated by (madeup)examples.

6 “….we need to stop discards, because throwing away food in a hungry world destroys our image and undermines data collection. Therefore I propose to land all catches and count them against quotas” from M. Damanaki, European Commissioner for Maritime Affairs and Fisheries, presentation to the European Parliament. Discuss the issues relating to discarding and whether you think that the proposed discard ban under the Common Fisheries Reform (2012) is likely to be effective. 

1. Aquaculture is the one of the sectors for commercial production of fishes contributing to more than half of the fishes produced all over the world through different ways supplying fish resources to a large bulk of global population. Maintaining sustainability in aquaculture refers to the production of fishes without harming the ecosystem and its various components in such a way that the ecological balance between different aquatic organisms is not interrupted. The criteria that should be considered in order to prepare a sustainable aquaculture system are to set up a proper objective and motive for the maintenance of sustainability during the development of the aquaculture and to ensure that important precautionary approaches are taken for the proper development of aquaculture sectors (Bush et al. 2013). Others criteria that should also be given be foremost priority are proper and correct amount of feeds requirement as more requirement increases the nutrient load and less results in inadequate food supply. Predator and prey interactions between the various fishes and the aquatic organisms also should be properly judged. Proper monitoring should be done to avoid the vulnerable habitats and high risk areas as both the aquaculture and the environment may face loss in terms of resource management. Pollution should be controlled. Proper management should be done between the fisheries and aquaculture. Care should be provided in order to achieve high level of welfare in the aquaculture businesses. Proper policy by the authorities should be implemented without the presence of any loopholes so that discrepancies in terms of excess resource use and destruction of the ecosystem can be prevented (Lazard et al 2014).

What is the ecosystem approach to fisheries management and where does aquaculture fit in?

2. An ecosystem approach to resource management in fisheries can be described as those approaches which would govern then proper production of fish resources to the present generation keeping in mind the objective that would prevent the jeopardizing of options of achieving this resource by the future generations so that they can also enjoy the benefit from a variety of ranges of goods and services obtained from the aquatic resources. This can be very well understood by an example. Fisheries without an ecosystem approach have resulted in reducing the abundance and spawning potential of the target fishes due to unplanned overfishing. Parameters like growth, maturation and many others are also found to have been  affected (Jennings et al. 2014). Exploitation of the resources by altering the age, size, sex ratio, genetics and species composition of the target resources had a serious impact on the ecological stability. Poor management and lack of sustainability planning resulted in overfishing breaking the stability of the ecosystem hampering the resources.

An ecosystem approach of resource management  in aquaculture includes a planned utilisation of varieties of different fishes, clams, crabs, prawns, mussels and others in a ecosystem so that a proper stable ecosystem is present in the environment with properly maintained food webs and food chains so that both the present and the future generations can enjoy the fish resources without harming the carrying capacity of the environment and harming the ecological balance by over production and exploitation of the resources. An example can be provided to describe the issues. A huge impact was found on the food web of the species of the particular region. Commercial extraction of a target species resulted in crashing down of the food cycle hampering the natural ecological balance of the particular biome (Laugen et al. 2014). Various other impacts were also recognized from this practice such as the lack of proper interactions between the different fishery resources and the environment, no proper planning of maintaining the sustainability while various fishery resources are utilized, poor management techniques and unplanned scientific approach resulting in destruction of the carrying capacity of a particular biome.

3. Global climate change has been the leading concern for a large number of environmentalists in all areas of researches as it had propounding impacts on every organisms present on the earth and aquaculture has not been an exception from it. There is a  rise of temperature for about 4 degree Celsius from the preindustrial era and such rise of temperature has affected the distribution of fishes in every water bodies on earth and has also affected the productivity of the fishes. Maintaining sustainability has become difficult and has therefore affected the communities whose living depends upon aquaculture. Rise of sea level due to global warming has affected the coastal fishing habitats with the change of rainfall pattern affecting the inland aquaculture systems (Bell et al 2013). Rising acidity in the oceans affected the production of shrimps, oysters, and corals as their shell formation gets affected due to disruption in calcification processes and loweing of Ph. Zooplanktons forming the base of marine food chain gets affected as they also possess calcite cells. Clown fishes suffer from behavioural disorders as they lose their hearing ability and judging ability to flee from predators and ornamental pisciculture also gets affected (Merino et al. 2012). Rising levels of sea water often results in floods and along the Mekong river the tonnes of bhasha fish production also gets affected due to the saltwater intrusion resulting from rising sea level and dams.

Recent advances and constraints in farming a named species

4. There are a number of differences between the lampreys and hagfishes. Lampreys dwell in both fresh and marine water and can live as both parasite and nonparasite. It may grow up to 1 metre. Hagfish is only marine and lives only as parasite. However like lampreys it also grows up to 1 metre.

Lamprey’s body is less slimy and is stout. It has a mouth which is terminal and pair of eyes are functional. However hagfish has feeble body the skin is much slimy. The eyes are degenerative and the position of the mouth is terminal (Nelson, Grande and Wilson 2016).

Lamprey’s teeth are larger and the tongue is not very well developed. It has a well developed brain and sexes are separate. However hagfish has well developed tongue, smaller teeth, less developed brain and the sexes are not separate that is they are hermaphrodite.

Lamprey has 20 cranial nerves and also possesses gill slits which are 14 in number. Hagfishes show 16 cranial nerves and 2 gill slits.

The lamprey possesses salivary glands where they secrete anticoagulant to remove the skin and flesh of their prey and suck blood. The hagfishes mainly are scavengers and eat dead fishes and do not possess any salivary glands (Hardisty 2013).

The development of lamprey is indirect that is their lifecycle consists of stages of development from larva. The hagfishes develop directly without going through the larva stage.

5. Discarding in fishing can be defined as the process that is used to release those species which are caught during the fishing practices which are unintentional and are therefore discarded in the water itself. Often this discard might contain other important commercial species beside the target species that results in additional benefit to the fisher man. The by catches which are not important are discarded back mainly due to the presence of restricted quota and is influenced by the choice of gear or due to fisherman’s behaviour (Bellman and Heery 2013).

Quantification of discarded is a highly difficult tasks and results always seem to vary. Assessment is done by the observer present at the site and time of the discards and has to take certain assumptions in mind for correct calculation. A linear relationship between the total landings and the discards has to be primarily assumed. From the discard rates that is studied from the the total landings of the fisheries, total quantity of the discards is then calculated. Under many circumstances it is found that, discard rates of many countries are considered negligible such as in artisanal and subsistence fisheries whereas in measuring discards during tuna fishing requires data from international tuna management. However, quantification purposes require more development especially including physical accounting and valuation of the ecological impacts in a broader spectrum. Equal probability and probability proportional are also conducted t quantify fishes discards.

The biggest impairments to elasmobranch conservation

Discards can be reduced by technical, administrative as well as economic means. Technical means comprises of improving the selectivity of fishes and taking out ways to reduce non-target species or make it profitable process to keep them. Devices and gear modification can help. Administrative measure contains limiting the number of vehicle to inhibit huge discards and to limit the timings and seasons for fishing so that discard amount can be restricted. Regulatory quotas also prevent excessive discarding by limiting the amount of fishes to be caught and others (Catchpole et al. 2014). Economic measures would include taxes, subsidies and quotas to restrict excessive discards because application of penalty makes fisherman concerned  and careful

6. The one on the left is the Beverton-Holt-Model and the other on the right is the Von Bertalanfy model.

The graph on the left has spawning potential on x axis and number of recruits on y axis. The graph on the right has time(years) as x axis and length (cm)as y axis

The graph o the left hand size give information that Recruitment is constant but it can never be specified. When there is no stock there is no recruitment (Bohner and Streipert 2016). Recruitment and selection are knife edge. This graph shows an exploited phase that portrays scramble competition. The fishing and natural mortality are considered to be a constant phenomena from the time they enter into the exploiters phase. A complete mixing occurs that lead to scramble competition for a particular resource. The graph on the right hand size shows that the length of a fish increases with time and after a certain time the rate of growth declines with increase in size (Lin et al. 2012).

References:

Bell, J.D., Ganachaud, A., Gehrke, P.C., Griffiths, S.P., Hobday, A.J., Hoegh-Guldberg, O., Johnson, J.E., Le Borgne, R., Lehodey, P., Lough, J.M. and Matear, R.J., 2013. Mixed responses of tropical Pacific fisheries and aquaculture to climate change. Nature Climate Change, 3(6), pp.591-599.

Bellman, M.A. and Heery, E., 2013. Discarding and fishing mortality trends in the US west coast groundfish demersal trawl fishery. Fisheries Research, 147, pp.115-126.

Bohner, M. and Streipert, S., 2016. Optimal Harvesting Policy For The Beverton–Holt Model. Mathematical biosciences and engineering: MBE, 13(4), p.673.

Bush, S.R., Belton, B., Hall, D., Vandergeest, P., Murray, F.J., Ponte, S., Oosterveer, P., Islam, M.S., Mol, A.P., Hatanaka, M. and Kruijssen, F., 2013. Certify sustainable aquaculture?. Science, 341(6150), pp.1067-1068.

Catchpole, T.L., Feekings, J.P., Madsen, N., Palialexis, A., Vassilopoulou, V., Valeiras, J., Garcia, T., Nikolic, N. and Rochet, M.J., 2014. Using inferred drivers of discarding behaviour to evaluate discard mitigation measures. ICES Journal of Marine Science: Journal du Conseil, 71(5), pp.1277-1285.

Hardisty, M.W., 2013. Biology of the Cyclostomes. Springer.

Jennings, S., Smith, A.D., Fulton, E.A. and Smith, D.C., 2014. The ecosystem approach to fisheries: management at the dynamic interface between biodiversity conservation and sustainable use. Annals of the New York Academy of Sciences, 1322(1), pp.48-60.

Laugen, A.T., Engelhard, G.H., Whitlock, R., Arlinghaus, R., Dankel, D.J., Dunlop, E.S., Eikeset, A.M., Enberg, K., Jørgensen, C., Matsumura, S. and Nusslé, S., 2014. Evolutionary impact assessment: accounting for evolutionary consequences of fishing in an ecosystem approach to fisheries management. Fish and Fisheries, 15(1), pp.65-96.

Lazard, J., Rey-Valette, H., Aubin, J., Mathé, S., Chia, E., Caruso, D., Mikolasek, O., Blancheton, J.P., Legendre, M., René, F. and Levang, P., 2014. Assessing aquaculture sustainability: a comparative methodology. International Journal of Sustainable Development & World Ecology, 21(6), pp.503-511.

Lin, Y.J., Su, N.J., Jessop, B.M., Chiang, W.C. and Sun, C.L., 2012. Errors in coefficient or expected value? Effects of different methods on simulated values for a linear model and the nonlinear von Bertalanffy growth model. J. Fish. Soc. Taiwan, 39(1), pp.23-34.

Merino, G., Barange, M., Blanchard, J.L., Harle, J., Holmes, R., Allen, I., Allison, E.H., Badjeck, M.C., Dulvy, N.K., Holt, J. and Jennings, S., 2012. Can marine fisheries and aquaculture meet fish demand from a growing human population in a changing climate?. Global Environmental Change, 22(4), pp.795-806.

Nelson, J.S., Grande, T.C. and Wilson, M.V., 2016. Fishes of the World. John Wiley & Sons.