Feeding aquaculture in an era of finite resources Naylor, Rosamond L; Hardy, Ronald W; Bureau, Dominique P ...
Proceedings of the National Academy of Sciences - PNAS,
09/2009, Volume:
106, Issue:
36
Journal Article
Peer reviewed
Open access
Aquaculture's pressure on forage fisheries remains hotly contested. This article reviews trends in fishmeal and fish oil use in industrial aquafeeds, showing reduced inclusion rates but greater total ...use associated with increased aquaculture production and demand for fish high in long-chain omega-3 oils. The ratio of wild fisheries inputs to farmed fish output has fallen to 0.63 for the aquaculture sector as a whole but remains as high as 5.0 for Atlantic salmon. Various plant- and animal-based alternatives are now used or available for industrial aquafeeds, depending on relative prices and consumer acceptance, and the outlook for single-cell organisms to replace fish oil is promising. With appropriate economic and regulatory incentives, the transition toward alternative feedstuffs could accelerate, paving the way for a consensus that aquaculture is aiding the ocean, not depleting it.
FISH Variants Guimarães, Nuno M; Azevedo, Nuno F; Almeida, Carina
Methods in molecular biology (Clifton, N.J.),
2021, Volume:
2246
Journal Article
FISH has gained an irreplaceable place in microbiology because of its ability to detect and locate a microorganism, or a group of organisms, within complex samples. However, FISH role has evolved ...drastically in the last few decades and its value has been boosted by several advances in signal intensity, imaging acquisitions, automation, method robustness, and, thus, versatility. This has resulted in a range of FISH variants that gave researchers the ability to access a variety of other valuable information such as complex population composition, metabolic activity, gene detection/quantification, or subcellular location of genetic elements. In this chapter, we will review the more relevant FISH variants, their intended use, and how they address particular challenges of classical FISH.
The local ecological knowledge (LEK) of fishers may help to fill the knowledge gaps about migration of tropical fish. We investigated fishers’ LEK on migratory patterns of seven fish species along ...550 km of the Tapajos River, in the Brazilian Amazon. We interviewed 270 fishers individually in four stretches of this river. The interviewed fishers indicated that three fish species do not migrate over long distances, while four fish species perform migrations, usually longitudinal migration from downstream to upstream reaches. Fishers also mentioned an increase in size of a large catfish species in the upstream stretches of the studied river, indicating the potential occurrence of spawning adults there. These results from fishers’ knowledge indicated that planned dams in the upstream reaches of the Tapajos River will threaten migratory fishes, small-scale fisheries and food security. Fishers’ LEK on fish migration contributed to raise testable biological hypotheses about fish spawning and feeding grounds, as well as the occurrence of distinct populations along the river. The analysis of the LEK of many fishers at several sites over a broad range is a cost-effective source of information on fish migration, supporting environmental impact assessment, fisheries management, and conservation in this and other tropical rivers.
The early development of teleost paired fins is strikingly similar to that of tetrapod limb buds and is controlled by similar mechanisms. One early morphological divergence between pectoral fins and ...limbs is in the fate of the apical ectodermal ridge (AER), the distal epidermis that rims the bud. Whereas the AER of tetrapods regresses after specification of the skeletal progenitors, the AER of teleost fishes forms a fold that elongates. Formation of the fin fold is accompanied by the synthesis of two rows of rigid, unmineralized fibrils called actinotrichia, which keep the fold straight and guide the migration of mesenchymal cells within the fold. The actinotrichia are made of elastoidin, the components of which, apart from collagen, are unknown. Here we show that two zebrafish proteins, which we name actinodin 1 and 2 (And1 and And2), are essential structural components of elastoidin. The presence of actinodin sequences in several teleost fishes and in the elephant shark (Callorhinchus milii, which occupies a basal phylogenetic position), but not in tetrapods, suggests that these genes have been lost during tetrapod species evolution. Double gene knockdown of and1 and and2 in zebrafish embryos results in the absence of actinotrichia and impaired fin folds. Gene expression profiles in embryos lacking and1 and and2 function are consistent with pectoral fin truncation and may offer a potential explanation for the polydactyly observed in early tetrapod fossils. We propose that the loss of both actinodins and actinotrichia during evolution may have led to the loss of lepidotrichia and may have contributed to the fin-to-limb transition.
The sustainability of global seafood supply to meet increasing demand is facing several challenges, including increasing consumption levels due to a growing human population, fisheries resources ...over‐exploitation and climate change. Whilst growth in seafood production from capture fisheries is limited, global mariculture production is expanding. However, climate change poses risks to the potential seafood production from mariculture. Here, we apply a global mariculture production model that accounts for changing ocean conditions, suitable marine area for farming, fishmeal and fish oil production, farmed species dietary demand, farmed fish price and global seafood demand to project mariculture production under two climate and socio‐economic scenarios. We include 85 farmed marine fish and mollusc species, representing about 70% of all mariculture production in 2015. Results show positive global mariculture production changes by the mid and end of the 21st century relative to the 2000s under the SSP1‐2.6 scenario with an increase of 17%±5 and 33%±6, respectively. However, under the SSP5‐8.5 scenario, an increase of 8%±5 is projected, with production peaking by mid‐century and declining by 16%±5 towards the end of the 21st century. More than 25% of mariculture‐producing nations are projected to lose 40%–90% of their current mariculture production potential under SSP5‐8.5 by mid‐century. Projected impacts are mainly due to the direct ocean warming effects on farmed species and suitable marine areas, and the indirect impacts of changing availability of forage fishes supplies to produce aquafeed. Fishmeal replacement with alternative protein can lower climate impacts on a subset of finfish production. However, such adaptation measures do not apply to regions dominated by non‐feed‐based farming (i.e. molluscs) and regions losing substantial marine areas suitable for mariculture. Our study highlights the importance of strong mitigation efforts and the need for different climate adaptation options tailored to the diversity of mariculture systems, to support climate‐resilient mariculture development.
Using the global mariculture production potential model (GOMAP) that accounts for changing ocean conditions, suitable marine area for farming, fishmeal and fish oil production, the dietary demand of farmed species, farm gate price, global seafood demand and farmed species production characteristics including specific feed conversion ratio and aquafeed crude protein inclusion level to project mariculture production potential (MPP) under two combined emissions and socio‐economic scenarios for 85 currently farmed species by the mid‐century relative to the 2000s.
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