An assessment of European bream Abramis brama (Linnaeus, 1758) fishery in the downstream of the Irtysh River in China

Abstract

Per-recruit analyses, with consideration for uncertainty in growth, natural mortality and maturity, were conducted for European bream Abramis brama in the downstream section of the Irtysh River in China to assess its status. The Chapman-Robson method produced an estimate of total mortality rate (Z) of 0.65 year À1. The natural mortality rates (M) were estimated as 0.13 and 0.26 year À1 , resulting in corresponding estimates of current fishing mortality rate (F cur) of 0.52 and 0.39 year À1 , respectively. All the estimates of yield per recruit (YPR), spawning stock biomass per recruit (SSB/R) and corresponding biological reference points (BRPs) were sensitive to M. The uncertainty of growth and maturity parameters had limited impacts on the estimates of BRPs, but had a large effect on the YPR and SSB/R outputs. Our findings indicate that A. brama may be at higher risk of growth overfishing than those of recruitment overfishing. In addition, increasing the t c to nine years might ensure that the spawning potential ratios (SPRs) are above the management targets under all ranges of F with comparatively small impacts on YPR regardless of M. In addition to providing a basic assessment for A. brama in the downstream of the Irtysh River in China, our study presents a comprehensive approach that may be useful for data-limited species in other fisheries.

Predicting the factors influencing the inter‐ and intraspecific survival rates of riverine fishes implanted with acoustic transmitters

“…As the spatial and temporal coverage of the PIT monitoring stations was relatively low in the study area, the contribution of acoustic signal loss to overall loss of bream from the study could have been under‐represented. Natural mortality rates (in the absence of fishing pressure) for bream populations in northern Europe and China have been estimated at 0.13 to 0.26 year −1 (Ding et al ., 2019; Kompowski, 1988). Although these estimates are not directly comparable to the rate here, they do suggest the rate of loss of tagged bream was higher than what might be expected by natural mortality alone.…”

Comparative Population Dynamics of Schizothorax wangchiachii (Cyprinidae: Schizothoracinae) in the Middle Reaches of the Yalong River and the Upper Reaches of the Jinsha River, China

“…Yield per recruit ( YPR ) and spawning stock biomass per-recruit ( SSB / R ) models were developed for the pooled data. The YPR and SSB / R were calculated using the following formulas [ 39 ]: where Y is the total catch; R is the total supplementary population; SSB is the total number of parent fish in the breeding population; SPR is the spawning potential ratio, defined as the value of dividing the unit supplementary amount of parental quantity by the unit supplementary amount of parental quantity without the fishing mortality rate under a certain fishing mortality coefficient; SSBR is the unit supplementary amount of parent fish; F is the fishing mortality rate; M is the natural mortality rate; t max is the maximum observed age; t r is the age at recruitment, which was the youngest age in the catch; t c is the age at first capture ( t max , t r and t c are obtained from age frequency distribution analysis); k is the growth parameter; t 0 is the hypothetical age at zero length; is the asymptotic length in the von Bertalanffy growth function; a and b are parameters in the weight–length relationship; G t is the proportion of mature fish at age t ( S. wangchiachii spawns just once each year), which was modeled by a previously published logistic function [ 40 ]; and S t is the gear selectivity coefficient for fish of age t and was set to ‘knife edge’ selectivity as follows: S t = 0( t < t c ) or 1 (t ≥ t c ) …”

“…Yield per recruit (YPR) and spawning stock biomass per-recruit (SSB/R) models were developed for the pooled data. The YPR and SSB/R were calculated using the following formulas [39]:…”

Dynamics of indices of metabolism in muscle tissue, liver and gonads of Abramis brama in different periods of the annual cycle

“…Among different systematic groups of freshwater fishes, a large share comprises the representatives of the Cypriniformes order. Among Cypriniformes, common bream Abramis brama (L.) are one of the most numerous industrial fish of freshwater water bodies and have an important place in the structure of their ecosystems (Kostić et al, 2016;Karabanov et al, 2018;Brodersen et al, 2019;Ding et al, 2019;Žák et al, 2019). The dynamics of accumulation of products of metabolism in the organism of common bream in different periods of annual cycle require separate and comprehensive analysis.…”