Reproductive variability in North Sea plaice, sole, and cod

Rijnsdorp, A.D.; Daan, N.; Beek, F.A. van; Heessen, H.J.L.

doi:10.1093/icesjms/47.3.352

Cited by 105 publications

(52 citation statements)

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“…Rowell (1993) also reported that this did not correspond to any notable change in growth rate. Rijnsdorp et al (1991) did not find a trend in variation of age at maturity in North Sea cod in the 1980s, when the SSB gradually decreased. Oosthuizen & Daan (1974) suggested that the shift to smaller size at maturity in North Sea cod seen by the 1970s was due to size selection brought about by the fishery, since there was no clear environmental covariate.…”

Section: Discussionmentioning

confidence: 62%

“…Previous studies on North Sea cod have demonstrated that there have been declines in age at maturity over the last century (Graham 1923, West 1970, Shopka 1971, Oosthuizen & Daan 1974, Rowell 1993, Cook et al 1999. Further, Rijnsdorp et al (1991) demonstrated that relative fecundity (developing oocytes g -1 body weight) in southern North Sea cod increased during the 1970s and 1980s. However, the relation of such changes in lifetime energy allocation to reproduction has received little attention, despite its significance to understanding possible fishing effects (Rochet et al 2000).…”

Section: Introductionmentioning

confidence: 95%

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Temporal and spatial variation in reproductive investment of Atlantic cod Gadus morhua in the northern North Sea and Scottish west coast

Yoneda

Wright²

2004

Mar. Ecol. Prog. Ser.

128

107

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The recent decline in many fish stocks has been accompanied by marked changes in age at maturity. However, there is little information on whether other components of reproductive investment have changed and the relative roles of phenotypic plasticity or genetic selection in such change. This study explored how reproductive investment in cod Gadus morhua from different regions around Scotland has changed between a period of high (1969, 1970) and low (2002, 2003) spawning-stock size. Maturity ogives indicated that inshore North Sea cod now mature at a smaller size and younger age than they did around 1970. The relationship between potential fecundity and size indicated that cod in the inshore region are now more fecund than 30 yr ago. Cod from the inshore region of the North Sea now have a higher fecundity at a given size and age than cod from the offshore region and the west of Scotland. There was no such spatial trend around 1970. Similarly, whilst the relative fecundity of cod in recent times is positively correlated with age, no such relationship was evident in 1969 and 1970. Nutritional influences on maturity and fecundity, particularly liver condition, were also evident from the recent study. However, the temporal and spatial differences in fecundity-size relationships were not consistent with a change in growth conditions, as there has been a significant decrease in body condition in recent times. Our findings regarding the temporal change in reproductive investment in the inshore North Sea region appear consistent with genotypic changes in life-history traits predicted to arise from intense periods of size-selective mortality.

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Section: Discussionmentioning

confidence: 62%

Section: Introductionmentioning

confidence: 95%

Temporal and spatial variation in reproductive investment of Atlantic cod Gadus morhua in the northern North Sea and Scottish west coast

Yoneda

Wright²

2004

Mar. Ecol. Prog. Ser.

128

107

View full text Add to dashboard Cite

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“…Conversely, positive effects of low levels of trawling have been either hypothesized (e.g., Rijnsdorp et al 1991, Jennings et al 2001, Daan et al 2005 or proved (Hiddink et al 2008, Giacalone et al 2010, Walsh et al 2012, mostly due to removal of the larger specimens and leading to three non-exclusive processes: (1) lower predation rates, resulting in higher benthic prey availability, (2) reduced competition among benthic fauna over food and space, which leads to increases in the production of the small benthos that fish feed on, and (3) proliferation of smaller, more productive benthic species (''farming the sea''). However, positive effects of low levels of fishing pressure on body condition by removal of intraspecific competitors (Giacalone et al 2010) or predators (Walsh et al 2012) were still very scarce.…”

Section: Discussionmentioning

confidence: 99%

Effect of intra‐specific competition, surface chlorophyll and fishing on spatial variation of gadoid's body condition

et al. 2015

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Abstract. Fish condition indices can be used as biological indicators of the health of individuals and are influenced by numerous external and internal drivers. Like most essential biological traits, they are very sensitive to the spatial heterogeneity occurring in marine ecosystems, which appears at many observational scales. This brings out different ecological processes that can only be revealed either regionally or locally. The scale-dependent spatial variability concerns not only environmental factors, but also anthropogenic activities such as fishing. Understanding these relationships is crucial for improving the spatial management of marine resources, because fish condition considerably affects the sustainability of populations. We explore the influence of density-dependent (intra-specific competition) and densityindependent variables (surface chlorophyll a concentration and fishing impact) on fish condition of three species of harvested gadoids (Merluccius merluccius, Phycis blennoides and Micromesistius poutassou) of the benthopelagic communities off the Balearic Islands (western Mediterranean). This area is characterized by high spatial heterogeneity in the environmental processes and fishing impact. Results show contrasting responses in body condition to the investigated covariates, with species-specific and ontogenetic differences sensitive to the spatial scale of analysis. Some of these responses occur at regional level, while others are more sensitive to local variation. Intra-specific competition shows a very clear effect, which depends on the ontogeny, identifying aggregation areas for recruits and limitation of resources for older individuals. Surface chlorophyll a has always a species-specific regional effect, despite gadoids have a more benthic behavior. Fishing effort displays a heterogeneous impact on fish condition. While spatially contrasting effects are observed at local scale, non-linear regional patterns occur, with positive effects of fishing pressure at intermediate levels. Models analyzing the influence of external drivers in essential fish biological traits such as body condition should consider the spatial variation in responses, especially in highly heterogeneous areas where anthropogenic activities occur. Failing to do so may hide local ecological processes that can be crucial for the persistence of fish populations, which is of paramount relevance for the regional assessment and spatial management of marine exploited resources.

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“…There may also be an effect on the proportion of adult hoki which develop and partake in the spawning migration (Livingston et al 1997). There is some strong evidence of links between fecundity and high recruitment (Schmitt 1978;Serebryakov 1990;Rijnsdorp et al 1991). The supply of food to adult fish has a major impact on both their somatic growth as well as their gonad development (Wooton 1979).…”

Section: Best Subset Regressionmentioning

confidence: 99%

Links between climate variation and the year class strength of New Zealand hoki (Macruronus novaezelandiae) Hector

Livingston¹

2000

New Zealand Journal of Marine and Freshwater Research

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Hoki (Macruronus novaezelandiae)Hector year class strength (YCS) varies substantially from year to year. In this study, potential links between hoki YCS estimates for western and eastern stocks, and time series of the Southern Oscillation Index (SOI), satellite sea surface temperatures (SST), synoptic weather patterns, depth of the mixed layer (western stock only), and wind speeds are explored. The results indicate that favourable recruitment in the western stock is correlated with a negative SOI and associated conditions such as lower SSTs, early onset of deep water mixing and synoptic weather patterns that result in a higher incidence of southwest (SW) flow. Favourable recruitment in the eastern stock appears to be correlated with periods of westerly flow, particularly from the SW, but also the north-west (NW). Regression studies showed that when inter-correlation was minimised, 95% of the variation in YCS of the western stock was explained by four variables-SOI in autumn, the onset of winter mixing, SST in spring, and NW spring weather patterns. In the eastern stock, 88% of the variation in YCS was explained by SW and NW winter weather patterns and the average speed of SW winds in winter through Cook Strait. Although the underlying mechanisms are not proven, the climate variables which appear to be linked to favourable recruitment for both western and eastern stocks, also favour upwelling and the physical transportation of larval hoki from the spawning grounds into their respective inshore nursery areas. M99026

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Reproductive variability in North Sea plaice, sole, and cod

Cited by 105 publications

References 0 publications

Temporal and spatial variation in reproductive investment of Atlantic cod Gadus morhua in the northern North Sea and Scottish west coast

Temporal and spatial variation in reproductive investment of Atlantic cod Gadus morhua in the northern North Sea and Scottish west coast

Effect of intra‐specific competition, surface chlorophyll and fishing on spatial variation of gadoid's body condition

Links between climate variation and the year class strength of New Zealand hoki (Macruronus novaezelandiae) Hector

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