Effect of fish length and nutritional condition on the fecundity of distressed Atlantic cod Gadus morhua from the Baltic Sea.

The disappearance of larger individuals and the decrease in individual body condition suffered by Atlantic cod Gadus morhua in the eastern Baltic during the past two decades can be expected to affect the stock reproductive output. To investigate this, female G. morhua were collected during the spawning and pre-spawning period in 2015-2016. The current individual potential fecundity (FP ) of eastern Baltic G. morhua was estimated and analysed in relation to total length (LT ) and indices of nutritional status such as body condition (K) and hepato-somatic index (IH ) using generalized linear models. In addition, the current prevalence of atresia and its potential relation to K were investigated. Moreover, a calibration curve to estimate FP from oocyte diameter, based on the autodiametric oocyte counting method, was established for the first time for eastern Baltic G. morhua and can be used for future fecundity studies on this stock. The results showed that FP was mainly positively related to fish length, but K and IH also contributed significantly to the variation in FP . The model predicted that fish with K = 1·2 have a FP 51% higher than fish of the same LT with K = 0·8. The prevalence of fecundity regulation by atresia was 5·8%, but it was found only in fish in the pre-spawning maturity stage and with low K. Temporal changes in biological features such as the length composition and individual body condition of eastern Baltic G. morhua, should be accounted for when estimating stock reproductive potential.

[1]  M. Casini,et al.  Modelling indices of abundance and size-based indicators of cod and flounder stocks in the Baltic Sea using newly standardized trawl survey data , 2017 .

[2]  K. Hüssy,et al.  Eastern Baltic cod recruitment revisited—dynamics and impacting factors , 2017 .

[3]  M. Casini,et al.  Hypoxic areas, density-dependence and food limitation drive the body condition of a heavily exploited marine fish predator , 2016, Royal Society Open Science.

[4]  Cody S. Szuwalski,et al.  Is spawning stock biomass a robust proxy for reproductive potential , 2016 .

[5]  A. Nissling,et al.  Fecundity regulation by atresia in turbot Scophthalmus maximus in the Baltic Sea. , 2016, Journal of fish biology.

[6]  O. S. Kjesbu.  Applied Fisheries Reproductive Biology: Contribution of Individual Reproductive Potential to Recruitment and Fisheries Management , 2016 .

[7]  K. Hüssy,et al.  Spatio-temporal trends in stock mixing of eastern and western Baltic cod in the Arkona Basin and the implications for recruitment , 2016 .

[8]  K. Hüssy,et al.  Eastern Baltic cod in distress biological changes and challenges for stock assessment , 2015 .

[9]  M. Hixon,et al.  Food for thought BOFFFFs: on the importance of conserving old-growth age structure in fishery populations , 2014 .

[10]  G. R. Fitzhugh,et al.  Energy acquisition and allocation to egg production in relation to fish reproductive strategies , 2014 .

[11]  H. Svedäng,et al.  Selective fishing induces density-dependent growth , 2014, Nature Communications.

[12]  M. Morgan,et al.  Does increased information about reproductive potential result in better prediction of recruitment , 2011 .

[13]  J. Tomkiewicz,et al.  Skipped Spawning in Fishes: More Common than You Might Think , 2011 .

[14]  Jesper Boje,et al.  Report of the Baltic Fisheries Assessment Working Group (WGBFAS), 10-17 April 2013, ICES Headquarters, Copenhagen , 2011 .

[15]  O. S. Kjesbu,et al.  Stereological calibration of the profile method to quickly estimate atresia levels in fish , 2010 .

[16]  A. Rijnsdorp,et al.  Fecundity, atresia, and spawning strategies of Atlantic herring (Clupea harengus) , 2009 .

[17]  H. Murua,et al.  Fecundity estimation of Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) of Georges Bank: Application of the autodiametric method , 2009 .

[18]  R. Oeberst,et al.  Seasonal maturity development of Baltic cod in different spawning areas: importance of the Arkona Sea for the summer spawning stock , 2009 .

[19]  Y. Lambert,et al.  Why Should We Closely Monitor Fecundity in Marine Fish Populations , 2008 .

[20]  J. Tomkiewicz,et al.  Seasonal prevalence and intensity of follicular atresia in Baltic cod Gadus morhua callarias L , 2008 .

[21]  R. Nash,et al.  Is fecundity in plaice (Pleuronectes platessa L.) down‐regulated in response to reduced food intake during autumn? , 2008 .

[22]  R. Nash,et al.  Maternal influences on egg and larval characteristics of plaice (Pleuronectes platessa L.) , 2007 .

[23]  C. T. Marshall,et al.  Comparison of various potential fecundity models for north-east Arctic cod Gadus morhua, L. using oocyte diameter as a standardizing factor , 2006 .

[24]  C. T. Marshall,et al.  Systematic bias in estimates of reproductive potential of an Atlantic cod (Gadus morhua) stock: implications for stock–recruit theory and management , 2006 .

[25]  O. S. Kjesbu,et al.  Timing and determination of potential fecundity in Atlantic cod (Gadus morhua) , 2006 .

[26]  R. Oeberst,et al.  The potential fecundity of cod in the Baltic Sea from 1993 to 1999 , 2005 .

[27]  M. Morgan,et al.  Effect of changes in reproductive potential on perceived productivity of three Northwest Atlantic cod (Gadus morhua) stocks , 2005 .

[28]  Y. Lambert,et al.  How variable is the fecundity within and between cod stocks , 2005 .

[29]  Marten A. Koops,et al.  Testing hypotheses about fecundity, body size and maternal condition in fishes , 2004 .

[30]  Gerd Kraus,et al.  Procedures to Estimate Fecundity of Wild Collected Marine Fish in Relation to Fish Reproductive Strategy , 2003 .

[31]  Y. Lambert,et al.  Using Environmental and Biological Indices as Proxies for Egg and Larval Production of Marine Fish , 2003 .

[32]  O. S. Kjesbu,et al.  Oocyte growth and fecundity regulation by atresia of Atlantic herring (Clupea harengus) in relation to body condition throughout the maturation cycle , 2003 .

[33]  J. Blanchard,et al.  Effects of condition on fecundity and total egg production of eastern Scotian Shelf haddock (Melanogrammus aeglefinus) , 2003 .

[34]  J. Tomkiewicz,et al.  Micro- and macroscopic characteristics to stage gonadal maturation of female Baltic cod , 2003 .

[35]  J. Tomkiewicz,et al.  Egg production of Baltic cod (Gadus morhua) in relation to variable sex ratio, maturity, and fecundity , 2002 .

[36]  G. Begg,et al.  Essential relationships incorporating the influence of age, size and condition on variables required for estimation of reproductive potential in Atlantic cod Gadus morhua , 2002 .

[37]  Olav Sigurd Kjesbu,et al.  A rapid method for estimation of oocyte size and potential fecundity in Atlantic cod using a computer-aided particle analysis system , 2001 .

[38]  P. Rago,et al.  Impacts of demographic variation in spawning characteristics on reference points for fishery management , 2001 .

[39]  F. Köster,et al.  Fecundity of Baltic cod: temporal and spatial variation , 2000 .

[40]  Y. Lambert,et al.  Natural mortality from poor condition in Atlantic cod (Gadus morhua) , 2000 .

[41]  C. T. Marshall,et al.  Total lipid energy as a proxy for total egg production by fish stocks , 1999, Nature.

[42]  O. S. Kjesbu,et al.  Temporal variations in the fecundity of Arcto-Norwegian cod (Gadus morhua) in response to natural changes in food and temperature , 1998 .

[43]  C. T. Marshall,et al.  Is spawner biomass a sensitive measure of the reproductive and recruitment potential of Northeast Arctic cod , 1998 .

[44]  G. Marteinsdóttir,et al.  Maternal influence on the size and viability of Iceland cod Gadus morhua eggs and larvae , 1998 .

[45]  T. Jorgensen,et al.  Effects of ration on the maturation and fecundity in captive Atlantic herring (Clupea harengus) , 1998 .

[46]  P. Solemdal.  Maternal effects — a link between the past and the future , 1997 .

[47]  Y. Lambert,et al.  Condition and energy reserves of Atlantic cod (Gadus morhua) during the collapse of the northern Gulf of St. Lawrence stock , 1997 .

[48]  Y. Lambert,et al.  Can simple condition indices be used to monitor and quantify seasonal changes in the energy reserves of cod (Gadus morhua) , 1997 .

[49]  J. Holm,et al.  Oocyte Recruitment in First-Time Spawning Atlantic Cod (Gadus morhua) in Relation to Feeding Regime , 1994 .

[50]  M. Burton,et al.  A critical period for nutritional control of early gametogenesis in female winter flounder, Pleuronectes americanus (Pisces: Teleostei) , 1994 .

[51]  Olav Sigurd Kjesbu,et al.  Fecundity, Atresia, and Egg Size of Captive Atlantic Cod (Gadus morhua) in Relation to Proximate Body Composition , 1991 .

[52]  O. S. Kjesbu.  A simple method for determining the maturity stages of Northeast Arctic cod (Gadus morhua L.) by in vitro examination of oocytes , 1991 .

[53]  O. S. Kjesbu,et al.  Ovulatory Rhythm and a Method to Determine the Stage of Spawning in Atlantic Cod (Gadus morhua) , 1990 .

[54]  J. Horwood,et al.  The effect of feeding levels on the fecundity of plaice (Pleuronectes platessa) , 1989, Journal of the Marine Biological Association of the United Kingdom.

[55]  J. Hislop,et al.  Observations on effects of feeding level on growth and reproduction in haddock, Melanogrammus aeglefinus (L.) in captivity , 1978 .

[56]  R. S. Dunn,et al.  Ration, Growth, and Measures of Somatic and Organ Condition in Relation to Meal Frequency in Winter Flounder, Pseudopleuronectes americanus, with Hypotheses Regarding Population Homeostasis , 1976 .

[57]  T. B. Bagenal.  The Relationship Between Food Supply and Fecundity in Brown Trout Salmo trutta L. , 1969 .

[58]  D. P. Scott.  Effect of Food Quantity on Fecundity of Rainbow Trout, Salmo gairdneri , 1962 .