Methods for estimating secondary production in marine Amphipoda

1981 ◽  
Vol 38 (9) ◽  
pp. 1019-1026 ◽  
Author(s):  
D. J. Wildish ◽  
D. Peer

For the 1971 year-class of Pontoporeia femorata from St. Margaret's Bay, N.S., secondary production was 11.06–13.61 g wet weight/m2 and annual turnover ratio was 3.64–4.78 as measured by three methods. These included cohort summation of losses, integrated production from the Allen curve, and size frequency, or modified Hynes methods. Sampling bias against early life history stages of amphipods collected with sieve meshes [Formula: see text] can be corrected by back calculation from population data thus enabling cohort-based estimates of secondary production to be made.Key words: secondary production, annual turnover ratio, Pontoporeia femorata, Crustacea, Amphipoda

1991 ◽  
Vol 48 (10) ◽  
pp. 1820-1828 ◽  
Author(s):  
Pierre Pepin ◽  
Ransom A. Myers

Recruitment variability is commonly associated with fluctuations in abundance of marine fish populations. Previous studies have focussed on stock-specific correlative or mechanistic models or on comparisons of recruitment variations of several stocks or species. The purpose of this study is to determine whether recruitment variability of commercial marine fish populations is associated with either size or the duration of early life history stages. The analysis was performed with data from 86 stocks representing 21 species of commercial marine fish. Univariate analysis shows that neither egg size nor the length at hatch is significantly correlated with recruitment variability. The change in length during the larval phase, which is representative of the duration of the stage, is significantly positively correlated with recruitment variability. Multivariate analysis shows that recruitment variability increases with increasing length at metamorphosis but that recruitment variability is poorly associated with length at hatch. The degree of serial correlation is related to the relative duration of egg and larval stages. The results clearly indicate that recruitment variability is linked to characteristics of early life history stages.


2021 ◽  
Vol 325 (4) ◽  
pp. 457-468
Author(s):  
L.A. Jawad ◽  
F. Mutlak ◽  
A.R.M. Mohamed ◽  
J.M. Al-Mamry ◽  
E.K. Hameed ◽  
...  

The finding of larval and juvenile specimens from the Omani coast of the Arabian Sea and the Arabian Gulf waters of Saudi Arabia and Iraq is reported for the first time. Based on available information, one larva was a leptocephalus, Conger sp. (family Congridae) and one larva of an acronurus stage belonging to the genus Acanthurus (family Acanthuridae). Also juveniles of the following families are included in the present study: Clupeidae – Tenualosa ilisha (Hamilton, 1822) and Nematalosa sp.; Dactylopteridae – Dactyloptena orientalis (Cuvier, 1829); Gobiidae – Acentrogobius sp.; Bothidae – Arnoglossus aspilos (Bleeker, 1851); Scatophagidae – Scatophagus argus (Linnaeus, 1766); Sparidae – Acanthopagrus arabicus Iwatsuki, 2013 and Sparidentex hasta (Valenciennes, 1830); Tetraodontidae – Lagocephalus sp. The discovery of the barred rather than spotted juveniles of S. argus collected from pure freshwater environment of the Shatt al-Arab River, Basrah, Iraq was remarkable; it raises questions whether there is more than one species within the nominal S. argus. For both larvae and juveniles of bothid flounders, the olfactory organ is a useful character for the examination of the developmental stage of the metamorphosing specimens. The occurrence of the different early life history stages of fishes from the three Arabian countries shows the needs them to be studied further so that inferences about the areas and periods of spawning and development of these fishes can be made more accurately.


2003 ◽  
Vol 111 (13) ◽  
pp. 1601-1607 ◽  
Author(s):  
Ruth H Milston ◽  
Martin S Fitzpatrick ◽  
Anthony T Vella ◽  
Shaun Clements ◽  
Deke Gundersen ◽  
...  

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