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LIFE-HISTORY PARAMETERS
LIFE-HISTORY PARAMETERS
Let me introduce you briefly to the topic of the first task of my Professional Practice: life-history parameters. Life-history parameters are the result of the evolution of each stock. They include intrinsic population parameters such as abundance, growth, survival, reproduction, maturity, and recruitment [1].
Many of the life-history parameters are usually collected during routine surveys to understand population dynamic and productivity for later use in stock assessment [2].
In fishery management, discontinuity in life-history parameters among populations of the same species is used to identify different stocks. This relies on the assumption that the differences in the phenotypes correspond to the interaction of environmental pressures and genetic heritage [3]. Therefore, differences in life-history parameters are considered a proxy for geographical isolation and/or limited interbreeding among populations [2]. To sum up:
Different environmental conditions + different genotypes
➡ Different life-history parameters
➡ Different stocks?
In this table, you can find all the descriptors that were gathered for each species, including life-history parameters.
6 DATA-DEFICIENT AZOREAN STOCKS: meeting the protagonists
6 DATA-DEFICIENT AZOREAN STOCKS: meeting the protagonists
The protagonists are 6 different species were identified as priority stock in the Azores [4], but little is known about their life-history parameters and current status. These are the reason why I worked on a literature review during the the first part of my professional practice. I was basically hunting for information among articles, reports, theses, online database, and other sources in the World Wide Web.
RESULTS: still too many gaps
RESULTS: still too many gaps
Results were organized in a collaborative database for later analyses and updates. In its final version, data on other six data-deficient Azorean species were added, hoping that in the future many more will join.
However the following table is clear: many information are still missing or are insufficient for stock delimitation.
WHAT'S NEXT?
WHAT'S NEXT?
Different data collected in field and lab, including life-history parameters, can be used to identify stocks.
A fish “stock” can be considered to be a group of randomly mating, reproductively isolated individuals with temporal or spatial integrity [1]. Stock identification is essential because stocks are used as management units.
Once exploitation impact on particular fishery is evaluated with stock assessment, fishery managers can develop evidence-based monitoring strategies and conservation measures, e.g. protection of nursery areas [5].
During my internship, I did my bit by collecting life-history parameters for our 6 underwater friends from literature. Other members of the Fisheries Research Group will use the data I gathered from literature and they will integrate them with novel results. Finally, the results of this joint effort are going to be submitted and hopefully published!
REFERENCES
REFERENCES
[1] Ihssen, P. E., et al. "Stock identification: materials and methods." Canadian journal of fisheries and aquatic sciences 38.12 (1981): 1838-1855.
[2] Begg, Gavin A. "Life history parameters." Stock identification methods (2005): 119-150.
[3] Begg, Gavin A., Jonathan A. Hare, and Daniel D. Sheehan. "The role of life history parameters as indicators of stock structure." Fisheries Research 43.1-3 (1999): 141-163.
[4] Santos, Régis, Wendell Medeiros Leal, and Mário Rui Pinho. "Stock assessment prioritization in the Azores: Procedures, current challenges and recommendations." Arquipelago. Life and Marine Sciences 37 (2020): 45-64.
[5] Smith, P. J., A. Jamieson, and A. J. Birley. "Electrophoretic studies and the stock concept in marine teleosts." ICES Journal of Marine Science 47.2 (1990): 231-245.
IMAGE CREDITS
IMAGE CREDITS
Serranus atricauda - Wendell Medeiros-Leal and Régis Santos
Other species: © Les Gallagher - Fishpics® & IMAR-DOP, UAç
Unless specified, all the pictures/videos were taken by me or crew members/friends.
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