Practical Approaches for Studying Sea Turtle Health and Disease
397
for their clinical relevance to humans and some domestic species. Even among
different species of mammals, the utility of specific plasma enzymes as biomarkers
of function or injury in particular organs or tissues varies (Loeb and Quimby,
1989; Meyer et al., 1992). This is partly related to the tissue origin of the predominant isozymes found in the blood and the degree to which these blood levels
change in response to tissue injury. In dogs and cats, for example, aspartate
aminotransferase (AST) and alanine aminotransferase (ALT) are useful markers
for liver status, because the isozymes expressed in liver contribute 90% of the
circulating enzyme activity. Conversely, in horses and ruminants, the predominant
source of plasma AST and ALT is skeletal muscle (Meyer et al., 1992). Basic
research into the clinical relevance of available tests for each species of sea turtle
is needed.
15.3.2 A B ASIC H EALTH A SSESSMENT P ROGRAM
Given the complexities and caveats discussed above, there is still a strong rationale
for developing health assessment programs and including health assessments routinely in other field studies that involve the capture and handling of turtles, even if
the primary purpose of the study is not health assessment. Because sea turtles are
encountered and handled frequently, the turtle biologist is an essential front-line
person in a general surveillance program for emerging health problems. Some fairly
straightforward and field-friendly techniques are required that will not be burdensome to the field researcher, but will provide useful information that can be compared
broadly across studies. Outlined below is what we consider to be both important
and feasible for most field studies. More sophisticated programs can build upon this
basic foundation.
15.3.2.1 Capture Data
Certain field data that are collected routinely in any turtle study provide important
background information in health assessment. These data include locality, date, and
time of effort; observation/capture methods used; weather; water conditions (temperature, tide); time and location of observation or capture of individual turtles;
species; age–size class (based on size measurements); and sex (if adult). Important
summary data for each sampling session include duration of effort, total number of
turtles of each species that were captured or observed, and number that were considered to have a health problem (below).
15.3.2.2 Behavioral Evaluation
It is important to record the turtle’s behavior prior to capture, if possible. For
example, was the turtle swimming, basking, or crawling normally, or was it found
floating or entangled? Did the turtle make a vigorous effort to elude capture or
escape, or was it “listless”? After being captured and landed, was it alert and
responsive to stimuli or weak and unresponsive? Did the turtle have symmetrical
use of its head and limbs? A basic neurologic examination can be performed to
assess both peripheral and central nervous system (Chrisman et al., 1997).
1123 book.book Page 397 Monday, November 11, 2002 11:11 AM
397
for their clinical relevance to humans and some domestic species. Even among
different species of mammals, the utility of specific plasma enzymes as biomarkers
of function or injury in particular organs or tissues varies (Loeb and Quimby,
1989; Meyer et al., 1992). This is partly related to the tissue origin of the predominant isozymes found in the blood and the degree to which these blood levels
change in response to tissue injury. In dogs and cats, for example, aspartate
aminotransferase (AST) and alanine aminotransferase (ALT) are useful markers
for liver status, because the isozymes expressed in liver contribute 90% of the
circulating enzyme activity. Conversely, in horses and ruminants, the predominant
source of plasma AST and ALT is skeletal muscle (Meyer et al., 1992). Basic
research into the clinical relevance of available tests for each species of sea turtle
is needed.
15.3.2 A B ASIC H EALTH A SSESSMENT P ROGRAM
Given the complexities and caveats discussed above, there is still a strong rationale
for developing health assessment programs and including health assessments routinely in other field studies that involve the capture and handling of turtles, even if
the primary purpose of the study is not health assessment. Because sea turtles are
encountered and handled frequently, the turtle biologist is an essential front-line
person in a general surveillance program for emerging health problems. Some fairly
straightforward and field-friendly techniques are required that will not be burdensome to the field researcher, but will provide useful information that can be compared
broadly across studies. Outlined below is what we consider to be both important
and feasible for most field studies. More sophisticated programs can build upon this
basic foundation.
15.3.2.1 Capture Data
Certain field data that are collected routinely in any turtle study provide important
background information in health assessment. These data include locality, date, and
time of effort; observation/capture methods used; weather; water conditions (temperature, tide); time and location of observation or capture of individual turtles;
species; age–size class (based on size measurements); and sex (if adult). Important
summary data for each sampling session include duration of effort, total number of
turtles of each species that were captured or observed, and number that were considered to have a health problem (below).
15.3.2.2 Behavioral Evaluation
It is important to record the turtle’s behavior prior to capture, if possible. For
example, was the turtle swimming, basking, or crawling normally, or was it found
floating or entangled? Did the turtle make a vigorous effort to elude capture or
escape, or was it “listless”? After being captured and landed, was it alert and
responsive to stimuli or weak and unresponsive? Did the turtle have symmetrical
use of its head and limbs? A basic neurologic examination can be performed to
assess both peripheral and central nervous system (Chrisman et al., 1997).
1123 book.book Page 397 Monday, November 11, 2002 11:11 AM