Reproductive Timing in Marine Fishes: Variability, Temporal Scales, and Methods

Abstract

Reproductive timing can be defined as the temporal pattern of reproduction over a lifetime. Although reproductive timing is highly variable in marine fishes, certain traits are universal, including sexual maturity, undergoing one or more reproductive cycles, participating in one or more spawning events within a reproductive cycle, release of eggs or offspring, aging, and death. These traits commonly occur at four temporal scales: lifetime, annual, intraseasonal, and diel. It has long been known that reproductive timing affects reproductive success, especially in terms of the onset of sexual maturity and the match or mismatch between seasonal spawning and offspring survival. However, a comprehensive understanding of variability in reproductive timing over species, populations, and temporal scales is lacking. In addition, there is a need to assess how variability in reproductive timing affects a population's resilience. Because natural selection occurs at the individual level, this necessitates an understanding of within-population (i.e., individual) variability in reproductive timing and how fishing may impact it through age truncation and size-specific selectivity or fisheries-induced evolution. In this paper, we review the temporal aspects of reproductive strategies and the four most-studied reproductive timing characteristics in fishes: sexual maturity, spawning seasonality, spawning frequency, and diel periodicity. For each characteristic, we synthesize how it has traditionally been measured, advances in understanding the underlying physiology, its role in equilibriumbased fish population dynamics, and its importance to reproductive success. We then provide a review of emerging methodology-with an emphasis on ovarian histology-to improve our ability to assess variability in reproductive timing both among populations and within populations.

Reproductive strategy of deep-sea and Antarctic octopods of the genera Graneledone, Adelieledone and Muusoctopus (Mollusca: Cephalopoda)

“…In small-egged (eggs of 1− 2 mm) fish and squid species, POF de generate in less than 24 h (tropical species, spawning temperature 20− 25°C) to ~48 h (temperate species, spawning temperature 10−19°C), and up to 6 wk at 9°C (Hunter & Macewicz 1985, Fitzhugh & Hettler 1995, Sauer et al 2002, Macchi & Pá-jaro 2003, Mace wicz et al 2003, Whittames 2003. In Atlantic cod they are easily identifiable even 3 mo after the spawning season ends in the Flemish Cap area (Lowerre-Barbieri et al 2011), where bottom temperatures are 3−4°C (Stein 1996). In Ant arctic fish it takes several months -up to 7 in Notothenia neglecta -for POF to degenerate at negative temperatures (Everson 1970, Butskaya & Faleeva 1987, La Mesa et al 2007), so complete de generation of POF in giant-egged (eggs of 10− 30 mm) cold-water octopods that reproduce at 0−4°C is likely to take a similar amount of time.…”

Editorial Note on Reproductive Biology of Fishes

“…15. The criteria used for the level of gonadal development that represents immature/mature individuals should be clearly stated (Lowerre-Barbieri et al 2011b). 16.…”

“…The method for estimating L m should be clearly stated. We suggest the use of maturity ogives (i.e., plots of proportion mature individuals against length class) upon which the logistic regression-the most commonly used method (Lowerre-Barbieri et al 2011b) -is fitted. Deviance statistics should be provided to facilitate checking the fit of the logistic model to the data (see Petrakis and Stergiou 1997).…”

Oocyte development and fecundity type of the Brazilian Snapper Lutjanus alexandrei Moura & Lindeman, 2007 (Perciformes: Lutjanidae)

“…The stage-specific and seasonal variation of oocyte size frequency distribution, seasonal variation in the percentage of different oocyte stages in individuals in spawning capable phase, and seasonal variation in the mean diameter of oocytes in the tertiary vitellogenesis stage in individual in spawning capable phase through spawning season are required (West, 1990;Hunter and Macewicz, 1985c;Murua et al, 2003;Brown-Peterson et al, 2011;Lowerre-Barbieri et al, 2011;Grande et al, 2013).…”