ASPECTS OF GROWTH IN CAPTIVE KILLER WHALES (ORCINUS ORCA)

Abstract

Morphometrics from 25 captive killer whales (11 captive‐born) were collected at SeaWorld parks from 1984 to 1995 to determine age‐specific growth parameters. For sexes combined, the body‐volume index was the most accurate predictor of body weight. However, predicting weight from total length was appropriate, although it may underestimate weight of pregnant animals. Among captive‐born calves, a Gompertz model was the best predictor of weight and length at age. Estimates for length and weight at birth were done using data from in utero and neonatal calves. For ages 1‐5 yr, models indicate that males grew in both weight and length at slower rates. Growth rates in males may surpass those of females at approximately 5‐6 yr of age.

Morphometric relationships of franciscana dolphin, Pontoporia blainvillei (Cetacea), off Rio Grande do Sul coast, southern Brazil

“…However, the best results were obtained by combining them in a single predictor, the body volume index. These findings confirmed previous cetacean studies where the best predictions of body mass value were obtained from equations involving both length and girth (Doidge, 1990;Read et al, 1993;Lockyer, 1995;Read and Tolley, 1997;Clark et al, 2000). Time of sampling may influence weight-length relationships through seasonal changes in body condition, thus the inclusion of girth in the equations used for indirect mass estimation is desirable.…”

“…In the case of the franciscana, mass estimation models can be found in the literature, but consist solely of simple regressions of mass versus total length (Kasuya and Brownell, 1979;Rosas, 2000;Rodriguez et al, 2002;Botta, 2005) and do not account for seasonal or developmental variations in body mass. Models which include both length and girth measurements as predictor variables are most reliable (Lockyer and Waters, 1986;Read et al, 1993;Lockyer, 1995;Read and Tolley, 1997;Clark et al, 2000). In the present work we propose specific models to estimate body mass from morphometric variables of franciscanas inhabiting Rio Grande do Sul, southern Brazil.…”

“…Steller sea lions, Eumetopias jubatus, Castellini and Calkins (1993); northern elephant seals, Mirounga angustirotris, Haley et al (1991); southern elephant seals, Mirounga leonina, Bell et al (1997); Weddell seals, Leptonychotes weddellii, Ireland et al (2006)) and cetaceans (fin and sei whales, Balaenoptera physalus and B. borealis, Lockyer and Waters (1986); bottlenose dolphins, Tursiops truncatus, Read et al (1993); harbour porpoises, Phocoena phocoena, Lockyer (1995); Read and Tolley (1997); killer whales, Orcinus orca, Clark et al (2000); estuarine dolphins, Sotalia guianensis, Rosas et al (2003)). In the case of the franciscana, mass estimation models can be found in the literature, but consist solely of simple regressions of mass versus total length (Kasuya and Brownell, 1979;Rosas, 2000;Rodriguez et al, 2002;Botta, 2005) and do not account for seasonal or developmental variations in body mass.…”

Reproduction, Growth and Development in Captive Beluga (Delphinapterus leucas)

“…For the most part, existing information has been derived from observation of wild stocks or post-mortem analysis of animals collected during native harvests [Brodie, 1971;Braham, 1984;Burns and Seaman, 1986;Doidge, 1990;Heide-Jrgensen, 1990;Heide-Jrgensen and Teilmann, 1994;Hier and Heide-Jrgensen, 1994]. Assuming accurate methods exist for aging the animals harvested [Clark et al, 2000], and despite access restricted by season, this type of data has been used to document certain biological functions including reproductive seasonality, growth, and development. Free-ranging male and female beluga have been estimated to be reproductively mature between 4-7 and 6-9 years of age, respectively [Brodie, 1971;Braham, 1984;Heide-Jrgensen and Teilmann, 1994].…”

“…With known ages and the ability to collect accurate serial morphometric measurements and serum samples (for reproductive hormone assays), captive populations provide a unique opportunity to improve our understanding of reproductive biology in this species [Clark et al, 2000]. The objectives of our research with captive beluga were to quantify seasonal endocrine changes in females (serum P) and males (serum T); to establish the age of sexual maturity; to document behaviors during parturition and the peri-parturient interval; to compare and contrast nursing patterns in normal and clinically distressed calves, and; to characterize growth rates in captive born calves and compare these data to estimates of growth rates in wild beluga.…”