Study on Reproduction of Captive Marine Mammals

Abstract

Abstract. The reproductive endocrinological characteristics of beluga, killer whale, spotted seal and bottlenose dolphin were evaluated and used in conjunction with applied reproductive research to enhance captive breeding programs. Results from 8 y of biweekly serum progesterone determination in a female beluga indicated that sexual maturity occured at approximately age 13, two to seven estrous cycles, lasting 37 ± 3.9 days, per yr began in April-May every year. Rectal temperature was positively correlated with serum progesterone levels and negatively associated with behavioral estrus. In five cases of pregnancy of two female killer whale, positive relationship was found between serum progesterone concentration and temperature during the first period of 18 month-gestation. In the normal parturitions (n=4), rectal temperature decreased 0.8 C lower than average rectal temperature during pregnancy. Sexual maturity of female killer whales occurred at age nine. Yearly contraception in the mono-estrus captive spotted seals (n=10) using a single dose of the progestagen (proligestone TM ; 5 or 10 mg/kg s.c.) was achieved in 94% (33/35) of the attempts over 5 yr when the hormone was administered two months prior to the breeding season. Artificial insemination trials (n=4) were conducted in female bottlenose dolphin (n=3) using fresh and frozen-thawed semen. Estrus synchronization using regumate (27 days) resulted in ovulation occurring 19 to 24 days post withdrawal. Conception was confirmed in 75% of the attempts, with two females successfully delivering calves. ousing dolphins in Japanese aquariums first began in the1950's, and only recently the era of promoting captive breeding has arrived [1]. Traditional research with marine mammals in Japan has come from post-mortem analysis of animals collected during whaling operations. However, many questions concerning biology and physiology of these animals cannot be learned using these methods. As a result, more emphasis is being placed on using captive animals for non-invasive research programs. Utilizing captive colonies of marine species has been possible to determine growth rates, sexual maturation, breeding period, copulatory behavior, gestation period, labor, parenting, and weaning. The breeding season and the estrous cycle of female bottlenose dolphins [2] were described with endocrine studies of captive animals, and it was found that some delphinids were spontaneous ovulators because ovulation occurred without males [3][4][5]. Analyzing serum progesterone concentrations, early pregnancy diagnosis was established and reproductive performance was improved [6,7]. For the male bottlenose dolphin, the seasonality of spermatogenesis and sperm characteristics were described through analysis of yearly changes in spermatozoa production and testosterone excretion [8][9][10][11]. For pinnipedia, it has been demonstrated that they have a period of delayed implantation, which are regulated by photo period and can be affected by nutritional variations [12,13]. In addition, shortly ...

Reproductive morphology of female Guiana dolphins (Sotalia guianensis)

“…Other studies evaluated sexual maturity by growth, measuring and weighing the gonads (Santos et al 2001, Rosas and Monteiro-Filho 2002, Da Silva et al 2007, Araújo et al 2007, Katsumata 2010, Perrin and Reilly 1984, Pomeroy 2011. However, studies reporting the microscopic anatomy of the female genital organs are scarce.…”

The high cost of reproduction in sea otters necessitates unique physiological adaptations

“…Overall, sea otters appear unique in their reproductive physiology. Although many species exhibit a decline in T core at the end of gestation (Eliason and Fewell, 1997;Fewell, 1995;Katsumata, 2010;Katsumata et al, 2006;Williams et al, 2011), this generally occurs in the days preceding parturition. For sea otters, this decline occurs over a 3 month period (Esslinger et al, 2014) and may be associated with metabolic changes (Table 1).…”

“…Declines in T core in the days preceding parturition have been documented in both terrestrial (Eliason and Fewell, 1997;Fewell, 1995;Melanie et al, 1988;Williams et al, 2011) and marine (Katsumata, 2010;Katsumata et al, 2006) mammals. In contrast, data from temperature-logging time-depth recorders (TDRs) implanted in wild sea otters have revealed a characteristic decline in T core by 1.5°C over the last 3 months of gestation (Esslinger et al, 2014).…”

A technique to artificially inseminate leafcutter ants

“…Artificial insemination is available for a wide range of species including humans (Chen and Wallach, 1994) and is frequently used for breeding domesticated animals such as cats (Axner, 2008), sheep (Evans and Maxwell, 1987), cattle, pigs, goats, rabbits, poultry, dogs, horses, and ostriches (see review by Foote, 2002), as well as for species requiring conservation breeding programs such as elephants, feline cats Wildt and Roth, 1997), gazelles (Holt et al, 1996), pandas , and dolphins (Katsumata, 2010). AI techniques are also available for commercially valuable crustaceans such as the tiger prawn (Benzie et al, 1995) and the lobster (Aiken et al, 1984) and for insects such as honeybees (Mackensen and Roberts, 1948;Ruttner, 1975), the silkworm Bombyx mori (Takemura et al, 1996), bumblebees (Baer and Schmid-Hempel, 2000), and the bedbug Cimex lectularius (Davis, 1964).…”