Utility of Condition Indices as Predictors of Lipid Content in Slimy Sculpin (Cottus cognatus)

Abstract

Slimy sculpin (Cottus cognatus) are increasingly being used as indicator species. This has primarily entailed measuring their condition, the assumption being that condition can be used as a surrogate for lipid content. While there is evidence to suggest this assumption is applicable to some fish, it has yet to be validated for C. cognatus. Further, there are several means by which one may calculate condition, the most commonly employed of which are indirect measurements of lipid content (namely, Fulton's K, somatic K (Ks), and Le Cren's relative condition factor (Kn)). We compared the ability of each of these morphometric indices to predict whole-body lipid content in C. cognatus. There was a moderate degree of evidence that Fulton's K, Ks, and Kn are reliable predictors (Ks and Kn in particular). Of the latter we recommend Kn be used because, unlike Ks, it does not require that fish be killed. And while Fulton's K did not perform quite as well, we consider it a sufficient substitute if the data necessary to calculate Kn are unavailable.

When and where are catfish fat fish? Hydro‐ecological determinants of energy reserves in the fork‐tailed catfish, Neoarius graeffei, in an intermittent tropical river

“…We chose these three metrics because together they provide both a general and a specific insight into energy reserves. Body condition indices are commonly used in fisheries to quantify the fatness of a fish for a given SL (Hards et al., 2019) and adjust for the cubic effect of SL on body weight that is observed in fish. Here, we describe body condition as the residuals from the relationship between ln(WW) ~ln(SL) as per Abujanra et al.…”

“…Body condition indices are commonly used in fisheries to quantify the fatness of a fish for a given SL (Hards et al, 2019) and adjust for the cubic effect of SL on body weight that is observed in fish.…”

Hepatic Steatosis in a Bullhead (Cottus gobio) Population from a High-Mountain Lake (Carnic Alps): Adaptation to an Extreme Ecosystem?

“…However, values of K did not show significant difference between fish from Dimon Lake and Degano Creek, indicating a robustness and good state of nutrition of both populations [36]. In this case, the use of Fulton's condition factor did not allow us to predict the lipid accumulation, as also previously suggested [37].…”

Patterns and predictors of condition indices in a critically endangered fish

“…We examined HSI and CF for four main reasons. First, both variables are widely used indicators of the general condition of fish, with HSI generally indicating the availability of shorterterm energy reserves (i.e., liver glycogen), protein, and lipid, and CF generally associated with muscle, protein and mesenteric fat (Boujard & Leatherland, 1992;Zamal & Ollevier, 1995;De Pedro et al, 2003;Hards et al, 2019). Second, in a recent experiment on cultured Delta Smelt, HSI was the most sensitive to fasting of the many biomarkers examined, becoming significantly depressed after four days without food at 15.9 °C, and CF was also relatively sensitive to food limitation, becoming significantly depressed after 7 days of fasting .…”