Short Communication |
Corresponding author: Justin C. Bagley ( jbagley@jsu.edu ) Academic editor: Rodolfo Reyes
© 2022 Justin C. Bagley, Maria Florencia Breitman, Jerald B. Johnson.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Bagley JC, Breitman MF, Johnson JB (2022) Length–weight relation for seven Neotropical freshwater fish species (Actinopterygii) endemic to Central America. Acta Ichthyologica et Piscatoria 52(3): 183-187. https://doi.org/10.3897/aiep.52.86467
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In the presently reported study, we estimated length–weight relation (LWRs) for seven species of freshwater fishes from Central America. Samples were collected using seines from 60 sites across Nicaragua, Costa Rica, and Panama during field expeditions conducted between 1997 and 2012. The fishes were preserved and transported to the lab, where their total weight (W) was measured (to nearest 0.0001 g) and standard lengths were taken (to nearest 0.01 mm). Data were collected from four livebearers (Poeciliidae), Alfaro cultratus (Regan, 1908), Phallichthys amates (Miller, 1907), Poecilia gillii (Kner, 1863), and Priapichthys annectens (Regan, 1907); the cichlids (Cichlidae), Parachromis dovii (Günther, 1864) and Parachromis managuensis (Günther, 1867); and a silverside (Atherinopsidae), Atherinella hubbsi (Bussing, 1979). Estimates of parameter b ranged from 2.936 (A. hubbsi) to 3.696 (P. gillii), while estimates of parameter a ranged from 1.7 × 10−6 (P. gillii) to 1.9 × 10−5 (P. managuensis). Parameter b estimates were greater than three, consistent with allometric growth, with the exception of P. annectens, P. managuensis, and A. hubbsi, for which t-tests failed to reject the null hypothesis of isometric growth. Our results provide the first LWR information for five (71%) of these species and may prove useful for data imputation or estimating the biomass of poeciliid, cichlid, and atheriniform fishes in Central American rivers in the future.
Costa Rica, ecology, freshwater fishes, LWRs, Nicaragua, Panama
Characterizing length–weight relation (LWRs) is an essential and routine task in fisheries science (
With ~525 species, the freshwater fish assemblage of Central America (CA) is highly diverse relative to its drainage area and displays marked uniqueness, with 10 fish biogeographic provinces and up to 59.2% within-region endemicity (
In the presently reported study, we describe LWRs for seven Neotropical fish species that are endemic to freshwater rivers and streams of CA. The majority of our focal species are non-game, ‘secondary’ fishes from families identified as having the capacity to disperse through marine environments (
The study area spans the CA Isthmus, from the Motagua Fault Zone in Guatemala, southeast to the Darién Isthmus, Panama (~523 000 km2; Fig.
Map of the study area. The boundaries of Central America (Motagua Fault Zone to the north, Darién Isthmus at Panama’s connection with South America) and some major physiographic elements are shown. Geographical sampling localities (n = 60) for this study are shown (black circles with white outlines; see accompanying Mendeley Data accession for additional details).
List of focal species examined in the presently reported study, with summaries of their taxonomic information, geographical distributions (
Family | Species name | Common name(s) | Geographical distribution | Current LWR n |
---|---|---|---|---|
Poeciliidae | Alfaro cultratus (Regan, 1908) | Knife-edged livebearer | N, CR, P | 0 |
Poeciliidae | Phallichthys amates (Miller, 1907) | Merry widow livebearer | G, H, N, CR, P | 0 |
Poeciliidae | Poecilia gillii (Kner, 1863) | Molly | G, H, N, CR, P | 0 |
Poeciliidae | Priapichthys annectens (Regan, 1907) | Olomina | CR | 0 |
Cichlidae | Parachromis dovii (Günther, 1864) | Guapote, wolf cichlid | H, N, CR | 1 |
Cichlidae | Parachromis managuensis (Günther, 1867) | Jaguar cichlid | H, N, CR | 2 |
Atherinopsidae | Atherinella hubbsi (Bussing, 1979) | Silverside | N, CR | 0 |
The standard modern equation of weight (W; body mass) in relation to length (L) takes the form
W = aLb
where the scalar a and exponent b are constants. Beginning with
log(W) = log(a) + b log(L)
(reviewed by
Raw length–weight data and collections data are archived in a Mendeley Data accession (archived version: https://doi.org/10.17632/kphrvvgwwz.1).
The inferred length–weight relation are presented in Table
Summary of length–weight relation for seven freshwater stream fishes from Central America.
Family | Species | n | n R | Standard length [mm] | Weight [g] | a [95% CIs] | b [95% CIs] | R 2 |
---|---|---|---|---|---|---|---|---|
Poeciliidae | Alfaro cultratus | 102 | 92 | 22.24–66.33 | 0.1005–4.3930 | 2.3 × 10−6 | 3.446 | 0.971 |
[1.5 × 10−6, 3.7 × 10−6] | [3.321, 3.570] | |||||||
Poeciliidae | Phallichthys amates | 44 | 42 | 15.96–42.27 | 0.0604–2.3576 | 5.3 × 10−6 | 3.439 | 0.953 |
[2.4 × 10−6, 1.2 × 10−5] | [3.199, 3.680] | |||||||
Poeciliidae | Poecilia gillii | 49 | 48 | 19.33–53.91 | 0.0829–3.510 | 1.7 × 10−6 | 3.696 | 0.965 |
[8.5 × 10−7, 3.6 × 10−6] | [3.490, 3.902] | |||||||
Poeciliidae | Priapichthys annectens | 69 | 63 | 17.09–51.94 | 0.0780–2.5573 | 1.5 × 10−5 | 3.0901 | 0.958 |
[8.9 × 10−6, 2.6 × 10−5] | [2.926, 3.254] | |||||||
Cichlidae | Parachromis dovii | 22 | — | 12.87–96.80 | 0.0390–23.691 | 1.4 × 10−5 | 3.1588 | 0.995 |
[9.9 × 10−6, 2.1 × 10−5] | [3.057, 3.260] | |||||||
Cichlidae | Parachromis managuensis | 7 | — | 32.37–55.51 | 0.9260–4.8221 | 1.9 × 10−5 | 3.1051 | 0.992 |
[6.1 × 10−6, 5.7 × 10−5] | [2.811, 3.399] | |||||||
Atherinopsidae | Atherinella hubbsi | 14 | — | 32.82–57.43 | 0.2509–1.3047 | 9.7 × 10−6 | 2.9359 | 0.932 |
[1.5 × 10−6, 6.2 × 10−5] | [2.458, 3.414] |
The LWRs presented herein had exponent values within the expected range of b = 2.5–3.5 for fishes (
Our study provides the first LWR data and modeling results for 5 out of 7 (71%) of our species. For the two species with previously recorded LWRs on FishBase, our results improve the estimates greatly. The Parachromis dovii LWR record on FishBase was estimated by R. Froese in (1999) from a single maximum total length (TL) record and arbitrarily assigned b = 3. We more confidently estimate b = 3.1588 for this species based on 22 specimens (Table
It is widely recognized that a number of different factors influence the growth and LWRs of fishes. Such factors include sex, health, the effect of gonad maturity on somatic growth, seasonality of resources, stomach fullness, sample size, and preservation techniques (e.g.,
We thank Jared B. Lee, Laura Scott, Joey T. Nelson, Eduardo Castro Nallar, Aaron H. Smith, Eric P. van den Berghe, and Spencer J. Ingley for invaluable assistance in conducting the fieldwork. The research was funded by a Brigham Young University Mentoring Environment Grant (JBJ) and Graduate Research Fellowship award (JCB), a US National Science Foundation Doctoral Dissertation Improvement Grant (DEB-1210883), and stipend support from US National Science Foundation grant OISE-PIRE 0530267 (JBJ).