Relationships between condition factors, parasite load and paternity in bluegill sunfish, Lepomis macrochirus

Abstract

SynopsisWe examined the relationship between non-polar lipid density, parasite density and paternity of male bluegill sunfish, Lepomis macrochirus, and four condition factors: (1) Fulton's condition factor, K; (2) the relative condition factor, K n ; (3) the relative mass index, W r ; and (4) the residuals from the geometric regression of mass on total length, C. Although the four factors were highly correlated to each other, only K and W r were significantly correlated with non-polar lipid density, explaining about 40% and 25% of the variation, respectively. K was also the best predictor of parasite density and was significantly correlated with the paternity of nesting males. These data provide support for K as a good indicator of individual energetic state and overall quality during the breeding period and demonstrate the importance of energetic state for understanding reproductive success in bluegill sunfish.

Effects of seascape context on condition, abundance, and secondary production of a coral reef fish, Haemulon plumierii

“…In mangrove tidal creeks, habitat fragmentation results in decreased food availability and slower growth rates in gray snapper Lutjanus griseus (Rypel & Layman 2008). Animals that experience faster growth rates, or are in better condition, may experience decreased predation risk (Sogard 1997, Booth & Hixon 1999, Booth & Beretta 2004, Johnson 2008 or higher reproductive output (Hutchings 1993, Fox 1994, Slotte & Fiksen 2000, Neff & Cargnelli 2004). Therefore, understanding how the surrounding seascape affects individual-based measures of habitat quality, like condition or growth, may provide useful information regarding optimal fish habitat.…”

Body condition indices as a rapid assessment of the abundance of introduced salmonids in oligotrophic lakes of southern Chile

“…For instance, K factor may vary by season (Trudel et al 2005), animal health status (e.g., Neff and Cargnelli 2004), differences in growth rates between juvenile and adults (He et al 2008, Rennie andVerdon 2008), life-history changes in the animal body form (e.g., during the reproductive season; Blackwell et al 2000) and changes in food availability (Pothoven et al 2001, Rennie andVerdon 2008). However, condition indices can be useful if used correctly by minimizing sources of variability.…”

“…However, condition indices can be useful if used correctly by minimizing sources of variability. For example, the K factor has been used as an indicator of recent feeding activity (Cone 1989), body energy reserves (Neff and Cargnelli 2004, Pangle and Sutton 2005, Herbinger and Friars 2008, energy densities (Trudel et al 2005) and physiological conditions (Rennie and Verdon 2008). In comparison, the advantages of Wr are that the standard weight compensates for inherent changes in the body form, and its values can be compared between fish of different lengths and from different populations (Ney 1999, Blackwell et al 2000.…”

Ectoparasitic sea lice (Lepeophtheirus salmonis and Caligus elongatus) infestations of wild, adult, one sea-winter Atlantic salmon Salmo salar returning to Scotland

“…Any departure from an exponent of 3 will, therefore, result in a length-dependence of individual fish CF. A measure more independent of length is the relative mass index, W R (W R = W/W S ), whereby W is the observed mass and W S the standard mass of individual fish calculated from a specific length-weight equation (Neff & Cargnelli 2004).…”

“…data). Host CF can be calculated for individual fish using a range of standard protocols based on mass-length relationships (Neff & Cargnelli 2004). Analysis of within-and between-year variation in CF for 13 year classes of mixed-stock 1SW salmon, netted on multiple dates during June to August each year at the same location as the present study (1993-2005, n = 4916; our unpubl.…”