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Long-term changes in population dynamics and life history contribute to explain the resilience of a stock of Micropogonias furnieri (Sciaenidae, Teleostei) in the SW Atlantic
Fisheries Research ( IF 2.4 ) Pub Date : 2021-01-16 , DOI: 10.1016/j.fishres.2021.105878
Manuel Haimovici , Leticia Maria Cavole , Jason M. Cope , Luís Gustavo Cardoso

We analysed the long-term changes in the population dynamics and life history of whitemouth croaker (Micropogonias furnieri) off Southern Brazil, to understand how four decades of heavy fishing (1976–2017) has affected its population dynamics. In the first three decades, size and age structure were eroded with the loss of the larger (> 60 cm total length) and older (>20 yrs. old) individuals. Individual growth increased sharply until the early 2000s and stabilized thereafter. The age at first maturity decreased by one year for females, the total mortality (Z) increased three-fold, and the stock size decreased approximately 90 %. Despite changes in the population structure due to intense fishing and high exploitation rates, the landings remained high until the late 2000s and in the last decade decreased less than expected by a former stock assessment. The resilience of the stock can be explained by its life history traits: (i) high fecundity, (ii) multiple spawning events during a protracted reproductive season in coastal waters, (iii) large estuarine nursery grounds unaffected by industrial fishing and (iv) faster growth and earlier sexual maturation due to the reduction in food competition and possibly evolution via gear selectivity. However, the stabilization of individual growth rates, the high rate of exploitation and the low spawning potential warn of the risk of further population decline and fishery collapse if intense fishing pressure continues.



中文翻译:

人口动态和生活史的长期变化有助于解释西南大西洋大西洋小po(Sciaenidae,Teleostei)种群的复原力

我们分析了巴西南部沿海的白嘴鲈(Micropogonias furnieri)的种群动态和生活史的长期变化,以了解四十年的繁重捕捞活动(1976-2017)如何影响其种群动态。在最初的三十年中,大小和年龄结构受到较大(总长度> 60 cm)和年龄较大(> 20岁)个体损失的侵蚀。个人增长急剧增加,直到2000年代初,然后稳定下来。女性的首次成熟年龄降低了一年,总死亡率(Z)增加了三倍,库存量减少了约90%。尽管由于激烈的捕捞和高剥削率导致人口结构发生变化,但到2000年代末期登陆量仍然很高,在过去十年中,登陆量下降的幅度小于以前的种群评估所预期的水平。种群的复原力可以通过其生活史特征来解释:(i)高繁殖力,(ii)在繁殖期长的沿海水域发生多次产卵事件,(iii)不受工业捕鱼影响的大型河口育苗场,以及(iv)由于食物竞争的减少以及可能通过齿轮选择性的进化而导致的更快的成长和更早的性成熟。但是,个人增长率保持稳定,

更新日期:2021-01-18
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