Reproductive Cycles of Males and Females
137
ducts and organs to facilitate the production of male and female gametes (spermatozoa and oocytes, respectively) (Licht et al., 1979; 1980; 1985; Owens and Morris,
1985; Wibbels et al., 1990; and for general reviews of seasonal reproduction in
reptiles, refer to Licht, 1982; Whittier and Crews, 1987).
5.3 OBSERVATION OF REPRODUCTIVE ANATOMY
Identification of basic reproductive parameters such as gender, age class, and reproductive state are prerequisites for most studies on reproductive cycles and physiological systems. The characterization of these parameters is logistically difficult and
often physically challenging for the researcher. Three methods are currently
employed by sea turtle biologists to obtain such information: necropsy, laparoscopy,
and ultrasonography. These definitive methods are preferred over the sole usage of
external features such as body size, weight, body condition, tail length, and endocrine
studies because these latter parameters do not permit definitive and quantifiable
characterization of various reproductive stages (Limpus and Reed, 1985; Limpus,
1992; Wibbels et al., 2000).
When working with threatened or endangered wildlife, examination of euthanized specimens to obtain reproductive data is often impractical. However, in situ
necropsies, or more detailed wet lab investigations on animals that die in markets
or are found dead on beaches (from natural causes or misadventure), can reveal
significant biological information such as gender, maturity, reproductive state, and
the reproductive history of adult females. General anatomical data are limited for
most species, as is information on developmental changes in gross and ultrastructural properties of reproductive organs and ducts (Limpus, 1992; Limpus and
Limpus, 2002a).
Another method allowing direct observation of reproductive organs and ducts
is laparoscopic surgery. The technical procedure, applications to sea turtle biology,
and associated benefits and problems have been well described over the last two
decades (Wood et al., 1983; Limpus, 1985; Limpus and Reed, 1985; Owens, 1999;
Wibbels et al., 2000). To reiterate, the main benefit is that laparoscopic examinations
allow direct and detailed color observation of reproductive organs and ducts in live
animals. They can be used to determine gender, maturity, and reproductive status of
individual turtles (Limpus and Reed, 1985; Wibbels et al., 1990; Limpus, 1992;
Limpus et al. , 1994a; 1994b; Wibbels et al. , 2000). Some limitations of laparoscopic
surgery are the high level of training required to conduct the surgery and interpret
the resultant image, and if the procedure is not performed correctly, it may cause
death of the turtle. Regardless, it still remains the most comprehensive nonlethal
method for the examination of internal organs. It has been used widely in Queensland, Australia, and the southeastern U.S. to collect reproductive data from C. caretta ,
Eretmochelys imbricata , N . depressus , and C. mydas as an essential basis for several
research projects. These include studies on annual reproductive cycles, population
demographic studies, physiological systems, and determination of reproductive state
for tracking studies (Wibbels et al ., 1990; Limpus, 1992; FitzSimmons, 1997; Limpus and Chaloupka, 1997; Braun-McNeill et al., 1999; Jessop et al ., 1999a; Chaloupka and Limpus, 2001; Limpus and Limpus, 2001; 2002b; Hamann et al ., 2002).
1123 book.book Page 137 Thursday, November 14, 2002 11:50 AM
137
ducts and organs to facilitate the production of male and female gametes (spermatozoa and oocytes, respectively) (Licht et al., 1979; 1980; 1985; Owens and Morris,
1985; Wibbels et al., 1990; and for general reviews of seasonal reproduction in
reptiles, refer to Licht, 1982; Whittier and Crews, 1987).
5.3 OBSERVATION OF REPRODUCTIVE ANATOMY
Identification of basic reproductive parameters such as gender, age class, and reproductive state are prerequisites for most studies on reproductive cycles and physiological systems. The characterization of these parameters is logistically difficult and
often physically challenging for the researcher. Three methods are currently
employed by sea turtle biologists to obtain such information: necropsy, laparoscopy,
and ultrasonography. These definitive methods are preferred over the sole usage of
external features such as body size, weight, body condition, tail length, and endocrine
studies because these latter parameters do not permit definitive and quantifiable
characterization of various reproductive stages (Limpus and Reed, 1985; Limpus,
1992; Wibbels et al., 2000).
When working with threatened or endangered wildlife, examination of euthanized specimens to obtain reproductive data is often impractical. However, in situ
necropsies, or more detailed wet lab investigations on animals that die in markets
or are found dead on beaches (from natural causes or misadventure), can reveal
significant biological information such as gender, maturity, reproductive state, and
the reproductive history of adult females. General anatomical data are limited for
most species, as is information on developmental changes in gross and ultrastructural properties of reproductive organs and ducts (Limpus, 1992; Limpus and
Limpus, 2002a).
Another method allowing direct observation of reproductive organs and ducts
is laparoscopic surgery. The technical procedure, applications to sea turtle biology,
and associated benefits and problems have been well described over the last two
decades (Wood et al., 1983; Limpus, 1985; Limpus and Reed, 1985; Owens, 1999;
Wibbels et al., 2000). To reiterate, the main benefit is that laparoscopic examinations
allow direct and detailed color observation of reproductive organs and ducts in live
animals. They can be used to determine gender, maturity, and reproductive status of
individual turtles (Limpus and Reed, 1985; Wibbels et al., 1990; Limpus, 1992;
Limpus et al. , 1994a; 1994b; Wibbels et al. , 2000). Some limitations of laparoscopic
surgery are the high level of training required to conduct the surgery and interpret
the resultant image, and if the procedure is not performed correctly, it may cause
death of the turtle. Regardless, it still remains the most comprehensive nonlethal
method for the examination of internal organs. It has been used widely in Queensland, Australia, and the southeastern U.S. to collect reproductive data from C. caretta ,
Eretmochelys imbricata , N . depressus , and C. mydas as an essential basis for several
research projects. These include studies on annual reproductive cycles, population
demographic studies, physiological systems, and determination of reproductive state
for tracking studies (Wibbels et al ., 1990; Limpus, 1992; FitzSimmons, 1997; Limpus and Chaloupka, 1997; Braun-McNeill et al., 1999; Jessop et al ., 1999a; Chaloupka and Limpus, 2001; Limpus and Limpus, 2001; 2002b; Hamann et al ., 2002).
1123 book.book Page 137 Thursday, November 14, 2002 11:50 AM