Gross Evidence of 

Human-Induced Mortality 

in Small Cetaceans 

Andrew J. Read 

Kimberly T. Murray 

U. S. Department of Commerce 

National Oceanic and Atmospheric Administration 

National Marine Fisheries Service 

NOAA Techcal Memorandwn NhiFS-OPR- 15 

July 2000 
This report was designed to assist stranding network members in the identification of 

evidence of adverse human interactions in stranded small cetaceans. Careful 

documentation of entanglement, gunshot wounds, vessel collisions, blast injury, and other 

human interactions may facilitate the diagnosis of a cause of death of a stranded dolphin 

or porpoise. Therefore, it is critical to establish physical criteria diagnostic of various 

sources of mortality. This manual describes external and internal evidence associated 

with entanglement in fishing gear, gunshot wounds, vessel collisions, and blast injury in 

small cetaceans. This report was prepared by the Nicholas School of the Environment at 

Duke University Marine Laboratoly in fulfillment of reference order 43AANF501263. 

Suggested citation: 

Read, Andrew J., and Kimberly T. Murray. 2000. Gross Evidence of Human-Induced 

Mortality in Small Cetaceans. U.S. Dep. Commer., NOAA Tech. Memo. NMFS-OPR-15, 

21 p. 

This technical memorandum series is used for documentation and timely communication 

of preliminary results, interim reports, or similar special-purpose information. Although 

the memoranda are not subject to complete formal review, editorial control, or detailed 

editing, they are expected to reflect sound professional work. The views and conclusions 

expressed by the authors are not necessarily those of the National Marine Fisheries 

Service. In addition, the mention of trade names or commercial firms is for information 

only and does not imply endorsement by the National Marine Fisheries Service. 

1 
Gross Evidence of 

Human-Induced Mortality 

in Small Cetaceans 

Andrew J. Read 

Kimberly T. Murray 

Nicholas School of the Environment 

Duke University Marine Laboratory 

135 Duke Marine Lab Road 

Beaufort, NC 2 8 15 6 

NOAA Technical Memorandum 

NMFS-OPR-15 

July 2000 

U. S. Department of Commerce 

Norman Y Mineta, Secretary 

National Oceanic and Atmospheric Administration 

D. James Baker, Under Secretary for Oceans and Atmosphere 

National Marine Fisheries Service 

Penelope D. Dalton, Assistant Administrator for Fisheries 
TABLE OF CONTENTS 

1.0 INTRODUCTION ............................................................ 1 

2.0 PHYSICAL EVIDENCE ASSOCIATED WITH ENTANGLEMENT IN FTSHING GEAR .................. .I 

2.1 Evidence Diagnostic of Entanglement in Gill Nets ............................ 1 

2.1.1 Evidence of entanglement ....................................... 2 

2.2.2 Postmortem!antemort:em injuries ................................. 4 

2.2 Non-Diagnostic Evidence of Entanglement in Gill Nets ........................ 4 

2.2.1 Body condition ................................................ 4 

2.2.2 Penetrating wounds ........................................... 5 

2.2.3 Mutilation .................................................. 6 

2.2.4 Scavenger damage ............................................ 6 

2.2.5 Hemorrhage ................................................. 7 

2.2.6 Respiratory system contents ..................................... '7 

2.2.7 Other Causes of Death ......................................... 8 

2.3 Entanglement in Purse Seines ............................................ 8 

2.4 Entanglement in Ropes and Lines ......................................... 8 

3.0 PHYSICAL EVIDENCE ASSOC~ATED WITH OTHER FORMS OF ANTHROPOGENIC TRAUMA ............ 9 

3.1 GunshotWounds ..................................................... 9 

3.2 Vessel Collisions ............... .................................... I1 

3.3 Blast-Induced Trauma ................................................ 12 

4.0 EXAMINING A SMALL CETACEAN FOR EVIDENCE OF HUMAN INTERACTION ................... 12 

4.1 General Information .................................................. 13 

4.2 External Examination ................................................. 13 

4.2.1 Body Condition ............................................. 13 

4.2.2 NetorLineMarks ................... .... .. ... ............ 3 

4.2.3 Fishing Gear Present and Retained ............................... 14 

4.2.4 Penetrating Wounds .......................................... 14 

4.2.5 Mutilation .................................................. 14 

4.2.6 HemorrhagingWruising ...................................... ~14 

4.2.7 Scavenger Damage ........................................... 14 
4.3 Internal Examination ................................................ -15 

4.3.1 Sub-Dermal Hemorrhaging ..................................... 15 

4.3.2 Broken Bones ............................................... 15 

4.3.4 Lung Contents .............................................. 15 

4.3.5 Stomach Contents ............................................ 15 

4.3.5 Histopathology Samples ....................................... 16 

4.3.6 Gross Pathology ............................................. 16 

4.4 Diagnosis .......................................................... 16 

5.0 EVALUATION OF HUMAN INTERACTIONS WITH SMALL CETACEANS ........................ 17 

6.0 ACKNOWLEDGEMENTS ........................................................ 19 

7.0 REFERENCES ............................................................... 20 
1.0 INTRODUCTION 

One can document evidence of anthropogenic trauma such as entanglement in fishing 

gear, vessel collisions, and gunshot wounds by 

careful evaluation of stranded marine mammals. 

Identification of such human-induced mortality 

and serious injury is an important function of the 

regional marine mammal stranding networks. 

Currently, several reference manuals exist to 

assist marine mammal network members in 

responding to stranding events, perform necropsies, and collect samples (Bonde et al., 1983; 

Hare and Mead, 1987; Geraci and Lounsbury, 

1993). However without proper training and 

experience, it can be difficult to identify some of 

the more subtle indications of anthropogenic trauma. This manual was designed to assist marine 

mammal researchers and stranding network 

members in the identification of evidence of 

adverse human interactions impacting stranded small cetaceans. 

Careful documentation of entanglement, 

gunshot wounds, vessel collisions, and blast 

injury may facilitate in the determination of a 

cause of death of a stranded small cetacea (i.e., 

dolphins or porpoises). Determining the cause of 

death is often difficult because postmortem autolysis or scavenger damage may obscure the physical evidence of these interactions. Therefore, it 

is critical to establish physical criteria diagnostic 

of various sources of mortality (Garcia-Hartmann 

et al., 1996; Kuiken, 1996). Such observations 

complement other methods of post-mortem 

examination, such as gross pathology and 

histopathology. 

Based on our extensive experience examining many injured dolphins and porpoises and on 

the observations from our colleagues, we have 

described in detail the gross evidence associated 

with fishing gear entanglement, gunshot wounds, 

vessel collisions, and blast injury. It is our hope 

that this report will assist marine mammal 

researchers and stranding network members 

with distinguishing between fatal injury due to 

human activities from those of natural causes. 

To this end, we have restricted our observations to 

gross evidence that can be documented by field 

workers familiar with basic marine mammal 

anatomy, but without any special knowledge of 

pathology. 

We have presented this information in three sections: 

Physical evidence associated with entanglement 

in fishing gear 

Physical evidence associated with other forms 

of human activity 

Procedures for examination of stranded small 

cetaceans and data documentation 

2.0 PHYSICAL EVIDENCE ASSOCIATED 

WITH ENTANGLEMENT IN FISHING 

GEAR 

Entanglement in fishing gear is the most 

common anthropogenic source of mortality for 

small cetaceans (Forney et al., 1999; Hill and 

DeMaster, 1999; Waring et al., 1999). The physical evidence associated with entanglement is 

specific to each combination of cetacean and fishing gear. Porpoises and dolphins killed in finemesh seine nets, for example, become trapped in 

the folds of the seine rather than entangled in the 

net itself and may not exhibit any external evidence of entanglement. In contrast, almost all 

dolphins and porpoises entangled in gill nets 

exhibit lacerations or indentations from the net 

material. Thus, the lesions caused by interactions 

with various types of fishing gear are very different. In this section, we will briefly describe gross 

evidence associated with entanglement in various 

types of fishing gear. 

2.1 Evidence Diagnostic of Entanglement in 

Gill Nets 

Over the past decade, we have examined over 

100 carcasses of small cetaceans known to have 

died in gill net fisheries. In all but one of these 

specimens, from five species and three families, 

we found clear external evidence of entanglement, primarily in the form of lacerations and 
indentations left from the net material. The type gear. These lesions have also been identified by 

of laceration varies with the net material. Marks other researchers as diagnostic of incidental morfrom monofilament nets usually appear as thin, tality of cetaceans in commercial fisheries 

distinct indentations in the skin of the animal (Kuiken et al., 1994; Kuiken 1996; Siebert et al., 

(Figure I). In contrast, multifilament gill nets 1996). Careful examination of the nature of these 

often leave impressions of the braided nylon in Lesions may indicate in which type of net the anithe skin (Figure 2). mai was entangled (i.e., monofilament or multifilament) and perhaps some indication of the size of 

the mesh. The degree of entanglement and, consequently, the severity of associated lesions can 

vary with the species and the type of net. Large 

animals, such as pilot and beaked whales, killed 

in large-mesh nets are often severely entangled 

and exhibit clear net marks over much of their 

body (Figure 3). Lacerations around the mouth of 

these larger animals may be associated with broFigure 1. Net marks around the rostrum of a harbor 

porpoise entangled in a sink gill net in the Bay of 

Fundy, Canada. 

Figure 3. Net marks around the head of a long-finned 

pilot whale entangled in a pelagic drift net on the 

continental shelf break of the northeastern U.S. 

Figure 2. Braided multifilament net marks around the 

dorsal fin of a common dolphin entangled in a pelagic 

drift net on the continental shelf break of the northeastern U.S. 

2.1.1 Evidence of Entanglement 

We consider the presence of unhealed, narrow, linear lacerations or indentations in the epidermis, most commonly around the head, dorsal 

Figure 4 Net marks encircling the cervical region of fin, flukes and flippers, to be diagnostic of entana harbor porpoise entangled in a sink glll net In the 

glement in gill nets. Any carcass exhibiting such Gulf of Ma~ne. 

lacerations or indentations should be assumed to 

have died as a result of an interaction with fishing 
ken or missing teeth caused by the net. Smaller 

animals, such as porpoises, may be caught in the 

net by a flipper or fluke lobe and exhibit only subtle signs of entanglement. Nevertheless, it is our 

experience that the vast majority of small 

cetaceans killed in gill nets exhibit external signs 

of entanglement in the form of net marks and, as 

noted above, we consider these lacerations and 

indentations to be diagnostic of entanglement. 

Lacerations and indentations left by net 

material are often deepest when present around 

the entire head (Figure 4) or thorax (Figure 5) of 

an animal, indicating that the animal may have 

Figure 7. Net marks on the leading edge of the flukes 

of a harbor porpoise entangled in a sink gill net in 

the Bay of Fundy, Canada. 

6), flukes (Figure 7) and dorsal fin (Figure 8) and 

are usually manifested as straight, narrow cuts 

into the epidermis. On the head, net marks often 

encircle the rostrum, or the head posterior to the 

eye. Net marks on the dorsal fin and flippers 

appear most commonly on the leading or trailing 

edges of the fins as thin, short lacerations, often 

breaking the skin. These lacerations may or may 

not be evenly spaced. These lacerations usually 

extend around both sides of the leading edge of 

the appendage, unlike other marks (such as gull 

- 

Figure 5. Net marks around the thorax of a common pecks) which are typically found only on one 

dolphin entangled in a pelagic drift net on the conti- side. Similar lacerations may appear around the 

nental shelf break of the northeastern U.S. 

Figure 6. Braided multifilament net marks encircling 

the flipper of a common dolphin entangled in a pelagic drift nct on the continental shelf break of the northeastern U.S. 

broken through several meshes of the net before 

becoming completely entangled. Lacerations are 

common on the leading edges of flippers (Figure 

Figure 8. Net marks on the leading and trailing edges 

of the dorsal fin of a harbor porpoise entangled in a 

sink gill net in the Bay of Fundy, Canada. 

leading and trailing edges of the tlukes, and may 

encircle the entire fluke lobes (Figure 9). Even 

when the net marks do not encircle the entire 

fluke lobe, it is often possible to match individual 

cuts, caused by individual strands of the net, on 
Figure 9. Net marks encircling the left fluke lobes of 

a harbor porpoise entangled in a sink gill net in the 

Gulf of Maine. 

both the leading and trailing edge of the flukes. 

Cracks in the skin caused by damage from freezing and thawing may be distinguished from net 

marks as the former tend to be jagged while the 

latter are sharp and clean. However, differentiation of lacerations caused by nets and cracks in 

the skin caused by desiccation in the freezer, or 

from repeated thawing and freezing, may be difFigure 10. Cracks in the epidermis caused by freezer 

desiccation on the dorsal surface of the flukes of a 

harbor porpoise stranded in Virginia. 

ficult (Figure 10). Therefore, it is important to 

conduct the external examination of a carcass 

prior to storage in a freezer. 

2.1.2 Postmortem/Antemortem Injuries 

Carcasses are often towed, moved or secured 

after death by ropes or lines tied around the taildence of entanglement and that associated with 

post-mortem events. It is also important to distinguish evidence of recent trauma from healed 

scars of past events. For example, a common dolphin killed in a pelagic drift net had healed line 

wounds around the rostrum and insertion of both 

flippers in addition to fresh lacerations, suggesting a previous, non-fatal entanglement. Many 

delphinids and ziphiids also bear fresh or healed 

lesions caused by social interactions with conspecifics. Tooth rakes are the most common form 

of these lesions, and these occasionally occur in a 

pattern similar to the marks left by the multifilament net material. 

2.2 Non-Diagnostic Evidence of Entanglement 

in Gill Nets 

Other forms of injuries are consistent with, 

but not diagnostic of entanglement in gill nets. 

These include penetrating wounds, missing 

appendages, sub-dermal hemorrhage, broken 

bones, and froth in the bronchi. We do not consider these features to be diagnostic of entanglement because they can originate from other types 

of trauma. 

2.2.1 Body Condition 

Most of the entangled specimens we have 

examined have been in good physical condition, 

with no evidence of emaciation (Figure 1 la). 

However, emaciated animals that have suffered 

stock or flippers; impressions and abrasions from Figure 1 la. A robust harbor porpoise lulled in a sink A A 

these lines are usually quite clear. Again, it is gill net in the Bay of Fundy, Canada. Note the conimportant to differentiate between physical evi- vex dorsal surfaces and the lack of any external neck. 
Figure 1 1 b. An emaciated harbor porpoise stranded in Figure 13. Severed caudal peduncle of a common 

virginia. Note the concave dorsal surfaces and pro- dolphin entangled in a pelagic drift net on the continounced neck, the sunken area just posterior to the skull. nental shelf break of the northeastern U.S. 

andlor died from a chronic medical problem may 

become entangled in fishing gear. An unusually 

thin blubber layer and atrophied neck or epaxial 

musculature (i.e., external depression posterior to 

the nuchal crest of the skull - pronounced neckline) are indicative of poor physical condition and 

may indicate the existence of chronic disease 

(Figure 1 1 b). 

Figure 14. Severed fluke blade of a common dolphin 

entangled in a pelagic drift net on the continental 

shelf break of the northeastern U.S. 

Figure 12. Puncture wound made post-mortem by a 

fisherman's gaff on the lower jaw of a harbor porpoise 

entangled in a sink gill net in the Bay of Fundy, 

Canada. 

2.2.2 Penetrating Wounds u 

Figure 15. Severed dorsal fin of a long-finned pilot 

Many porpoises and dolphins killed in fish- whale entangled in a pelagic drift net on the continen 

tal shelf break of the northeastern U.S. 

eries exhibit small penetrating wounds caused by 

the gaffs used by fishermen to retrieve the ani- the vessel. Other penetrating wounds are made 

mals from the water (Figure 12). These wounds by stab probes used by fisheries observers to 

usually occur around the head and cervical measure core body temperatures in the epaxial 

regions, as the animal hangs tail down alongside musculature near the dorsal fin. Any small 
cetacean carcass examined and discarded overboard by a NMFS fisheries observer should be 

readily identified by a plastic, numbered, tail tag 

(Figure 9). 

2.2.3 Mutilation 

Fishermen often mutilate the carcasses of 

small cetaceans to facilitate disentanglement. 

This is particularly true for large animals that are 

severely entangled. In such cases, the flukes, flippers, or dorsal fin may be cleanly severed 

(Figures 13- 1 5). Fishermen and observers working aboard drift net vessels have noted that it is 

often extremely difficult to remove the carcasses 

of dolphins, pilot whales, and beaked whales 

from their nets. In contrast, small-bodied animals, such as porpoises, are often disentangled 

without mutilation. Fishermen will sometimes 

make a longitudinal slit along the ventral surface 

of the abdomen before discarding the carcass, in 

Figure 17. Dismembered carcass of a harbor porpoise stranded in New Jersey. Note the net mark 

encircling the body just anterior to the insertion of the 

flipper and the clean edges of knife cuts. 

pits made in the epidermis by scavenging 

amphipods (Figure 18) to extensive external and 

internal damage caused by amphipods and hagfish (Figure 19). It is our experience that these 

benthic scavengers first attack the areas around 

the belief that it will be less likely to float and 

reach shore (Figure 16). Occasionally the mutilation of carcasses is more severe (Figure 17). 

Figure 18. Mild damage caused by benthic scavengers to the head of a harbor porpoise entangled in a 

sink gill net in the Bay of Fundy, Canada. 

Figure 16. Longitudinal slit made in the abdomen of 

a harbor porpoise scarcass stranded in North 

Carolina. Note the clean edges of the knife cut. 

2.2.4 Scavenger Damage 

The degree and type of scavenger damage 

varies with the species and situation. For example, most harbor porpoise carcasses retrieved 

from sink gill nets exhibit damage from benthic 

scavengers. This damage ranges from superficial 

the eyes, mouth, axillae and genital regions 

(Figure 20). In some cases the damage is so 

extensive that it is impossible to judge whether 

signs of entanglement exist in these areas. 

Entangled small cetaceans may also bear evidence of scavenging by sharks particularly in 

warmer waters. For example, a beaked whale 

carcass we retrieved from a pelagic drift net had 

been scavenged by blue sharks (Prionace glauca), which had left several bite marks approximately 20 cm in diameter along the ventral mid- 
enger damage may be difficult to distinguish from 

extensive benthic scavenger damage. 

2.2.5 Hemorrhage 

Figure 19. Extensive damage caused by benthic scavengers to the head of a harbor porpoise entangled in a 

sink gill net in the Bay of Fundy, Canada. Note the 

net marks on the rostrum. 

line of the animal. Gulls (Figure 29) may also 

heavily scavenge stranded carcasses. This damage usually occurs while the carcass is on the 

beach but also may happen while it was floating 

in the water. Gull scavenger damage begins as a 

series of small 1-2 cm scrapes into the epidermal 

layers. These scrapes are very distinctive, usually quite shallow (<5 mm) and numerous. If the 

damage caused by gulls occurred while the carcass was floating in the water then it might be 

restricted to a specific side or region. As scavFigure 20. Damage caused by benthic scavengers 

around the eyes and axillae of a harbor porpoise 

entangled in a sink gill net in the Bay of Fundy, 

Canada. 

enging proceeds the body cavity is usually penetrated and the birds begin to eviscerate the carcass. When the carcass reaches shore, gulls often 

attack the jaw area first to gain access to the lipidrich mandibular fat pads. With the exception of 

the telltale epidermal scrapes, extensive gull scavThe carcasses of many dolphins and porpoises killed in fishing gear exhibit sub-dermal hemorrhage, particularly in the dorsal and lateral cervical regions. Hemorrhage is the escape of blood 

Figure 21. Sub-dermal hemorrhage in the cervical 

region of a harbor porpoise entangled in a sink gill 

net in the Gulf of Maine. 

from ruptured vessels, often caused by trauma 

(Bonde et al., 1983; Kuiken, 1996; Figure 21). 

We believe that this hemorrhage may be caused 

by the restraint imposed on the animal's head 

while it struggles in the net. It is worth noting 

that this form of hemorrhage is seldom evident on 

external examination in these specimens. Many 

dolphins killed in fishing gear also exhibit antemortem broken bones and associated blood clots 

and macerated soft tissue. Typically these bones 

include mandibles, flippers, ribs or the vertebral 

processes clots. Some bones may be broken postmortem, when the carcasses are dropped on deck 

or swing against the side of the vessel. Look 

carefully for signs of blood infiltration into the 

region of the broken bone and signs of hemorrhage in the surrounding tissue. Ante- and postmortem fractures can be definitively differentiated by histopathological analysis. 

2.2.6 Respiratory System Contents 

Often a white froth or a mix of forth and 

blood tinged fluid can be noted in the bronchi of 
dolphins and porpoises killed in fishing gear. On 

several occasions, fisheries observers have noted 

white foam venting from the blowhole as the carcass was retrieved from the net. Several 

researchers have discussed the appearance and 

contents of the lungs and airways as diagnostic of 

death in fishing gear (Garcia-Hartmann et al., 

1996; Kuiken, 1996; Kuiken et al., 1996). As 

noted by Lipscomb (1996), foam in the upper and 

lower air passages is considered an important sign 

of death by human drowning victims, but is not 

specific to this cause of death. Researchers have 

also suggested that diatoms and other marine 

flora in the lungs are indicators of death by submersion, but these organisms may be introduced 

into the airways post-mortem (Larsen and Holm, 

1996). In our experience, the presence of froth, 

blood tinged or accompanied by fluid, is a common, but not a diagnostic feature of death caused 

by entanglement in fishing gear. We also agree 

with Kuiken et al. (1996) that the presence of seawater in the respiratory tract is not a useful criterion for the diagnosis of entanglement, as we 

rarely noted its presence the animals we examined. 

2.2.7 Other Causes of Death 

It is worth noting that sometimes carcasses 

exhibit many of the physical signs of entanglement when death occurred from another cause. 

For example, harbor porpoises killed by blunt 

trauma inflicted by bottlenose dolphins exhibit 

several types of injuries. These include penetrating wounds, sub-dermal hemorrhage and broken 

bones (Ross and Wilson, 1996), all of which are 

features commonly associated with entanglement. Careful examination of these wounds may 

rule out entanglement as a potential cause of 

death. Appendages that have been cleanly severed from the body are strongly suggestive of 

human interactions. It is possible, however, that 

such mutilation can occur on the beach (Kuiken, 

1996). Therefore, this type of evidence is not sufficient to confirm physical interaction with fishing gear. 

2.3 Entanglement in Purse Seines 

The external evidence we have documented 

from animals killed in purse seines is very different from that of animals entangled in gill nets. 

We have examined many porpoises killed in herring purse seines that bore no external marks 

whatsoever from the nets. One porpoise, tagged 

and released from a seine two weeks before it 

became trapped and died in another seine, 

showed no external marks from either episode. 

The only external marks present on many porpoises and dolphins killed in purse seines are 

small abrasions of the rostrum or of the leading 

edges of flukes and dorsal fin, rather than welldefined lacerations or indentations. This is consistent with the method of capture, which is by 

entrapment in folds of the fine-meshed net, rather 

than by entanglement in the webbing of the net. 

Thus, it is important to note that not all carcasses 

killed in commercial fishing gear will exhibit 

external marks from the nets. 

Porpoises and dolphins killed in purse seines 

may exhibit many of the other lesions consistent 

with entanglement in gill nets. Some carcasses, 

for example, have penetrating wounds, made by 

the gaffs used by the fishermen. In general, it is 

not necessary to mutilate the animals to disentangle them from a purse seine. Approximately half 

of the specimens we have examined from purse 

seines exhibit sub-dermal hemorrhage, most frequently in the cervical region and occasionally 

over the head, thorax and abdomen. Therefore, 

animals captured in some types of fishing gear 

may exhibit a variety of non-specific lesions consistent with entanglement, but no distinctive 

marks from the gear itself. 

2.4 Entanglement in Ropes and Lines 

Interactions with ropes and lines may not be 

fatal, at least in the initial entanglement. For 

example, there have been observations of live bottlenose dolphins carrying lines, dragging crab 

pots, or becoming immobilized after entanglement in crab pot lines in coastal waters of the 
southeastern U.S. (W. McFee, NMFS/SEFSC & 

R. Wells, Chicago Zoological Society, personal 

communication). The majority of marine mammal interactions with pelagic longlines involve 

animals that are hooked and released alive 

(Angliss and DeMaster, 1998). Although their 

fate after release is not known, many of these animals are released with hooks embedded in some 

portion of their body. There are also an increasing number of interactions between coastal bottlenose dolphins and recreational fishing - - gear, in 

which the dolphins are hooked or entangled in Figure 23. Stranded bottlenose dolphin in North 

monofilament fishing line (Wells et al., 1998; Carolina with line extending through dermis and into the 

underlying connective tissue. The line had abraded com- Figure 22). pletely through both humeri, Photo courtesy of Bill 

~c~ellan and An Friedlaender, UNC Wilrninpton. 

Figure 22. Stranded bottlenose dolphin in Sarasota, FL 

wrapped in recreational monofilament fishing line. Photo 

courtesy of R.S. Wells, Chlcago Zoological Society. 

Evidence of entanglement in ropes or lines is 

usually obvious. There are often pronounced 

abrasions in areas where the line has wrapped 

around the body or appendages. These abrasions 

are typically found around flippers, the caudal 

peduncle and at the insertion of the flukes. If an 

animal has survived the initial entanglement and 

carried gear for some time before its death, the 

abrasions may be severe, extending into connective tissue below the blubber, muscle and even 

bone (Figure 23), and may be accompanied by 

local or systemic infections. In such cases, the 

entangled animals may strand with the gear still 

attached. Any gear found should be retained, so 

that the nature of the interaction can be fully documented. If entanglement in monofilament line is 

discovered or suspected, a thorough examination 

should be made of the oral cavity, esophagus and 

forestomach during necropsy, for the presence of 

hooks. Line may become wrapped around the 

epiglottal beak if fishing lures or bait have been 

ingested (Gorzelany, 1998). Dolphins and porpoises killed in longline, crab or lobster pot gear 

may exhibit many of the same types of gross 

internal evidence as those entangled in other 

types of fisheries. 

A note of caution should be stated concerning the use of tail tags and towlines by stranding 

personnel. The use of these items can obscure 

existing impressions made by the line or rope and 

make evaluation of a carcass difficult. Whenever 

possible, it is important to examine the carcass for 

evidence of adverse human interaction before 

these items are attached. In addition it is important to carefully record how and where tail tags 

and towropes were used to avoid spurious diagnoses if the carcass is to be evaluated by others at 

a later date. 

3.0 PHYSICAL EVIDENCE ASSOCIATED 

WITH OTHER FORMS OF ANTHRO 

POGENIC TRAUMA 

3.1 Gunshot Wounds 

Gunshot wounds vary in nature depending on 

the type and caliber of weapon used and the proximity to the animal when the weapon was fired. 
Single bullet wounds are easy to distinguish from 

those caused by shot pellets by their size and 

number. Entry wounds may be blackened or 

singed if the weapon was fired at close range. 

The size of an entry wound is not a reliable indicator of the caliber of weapon used, as the elasticity of the skin and proximity of the weapon 

affect the diameter of the entry wound. An abrasion collar often extends around the entry point 

with even, smooth edges, where the skin has 

it is imperative that a suite of histopathological 

samples be taken from tissues adjacent to the 

wound to determine whether the animal was shot 

ante- or post-mortem. Carefully note the exact 

location and size of the wounds on the data sheet, 

and describe all internal evidence observed. 

Mark the wound with a tag containing animal 

identification number and date. Photograph both 

the external and internal areas affected by the 

gunshot wound. Before opening the wound site, 

carefully probe with a blunt object to determine if 

the wound is penetrating and to determine the 

approximate path of the projectile. Extract the 

projectile with a gloved hand, not with metal forceps (i.e., metal forceps could leave a scratch on 

the bullet). Wash any bullets or shot in fresh 

water and store in a sealed paper envelope for 

future forensic analysis. Sometimes gunshot animals are missed due to the variability of entry 

wounds andlor the entry wound heals rapidly. 

Radiographs may help in locating the projectiles, 

Figure 24. Entry wound from close-range shotgun as the trajectory may not be linear after entering 

blast that killed a harbor porpoise in a herring weir in the animal. 

the Bay of Fundy, Canada. Note the inversion of the 

skin into the perimeter of the wound. Unlike the wounds produced by scavengers, 

inverted into the wound (Figure 24). Exit wounds which are distributed over certain regions of the 

may be of any size and are often characterized by carcass, gunshot wounds are usually isolated on 

jagged, irregular lacerations, eversion of the skin the carcass and surrounded by relatively undammargins and marked removal of tissue. 

It may be difficult to identify gun shot 

wounds in small cetaceans if time has passed 

since the wound was made and the superficial 

lesions have healed. In such cases, radiography 

may assist in diagnosis and facilitate location of 

projectiles, as their trajectory is not always linear 

after entry. 

If you suspect a wound has been caused by a 

gunshot, perform a careful internal examination Figure 25. Multiple entry wounds from a shotgun - 

of the carcass. Follow the path of the wound into blast that killed a harbor porpoise in a herring weir in 

the Bay of Fundy, Canada. Note the relatively unaf- the animal. There may be hemorrhagic tissue and fected area around the wounds. 

blood clots around the path of the projectile(s). 

Bones may be broken, particularly the skull, vertebrae and ribs, depending on the location of the aged skin (Figure 25). Damage from scavengers 

wound. The presence of a bullet or pieces of shot is usually shallower than gunshot wounds and 

is diagnostic of a gunshot wound. In such cases, more erratic in nature. 
3.2 Vessel Collisions from propellers consist of parallel, evenly spaced 

cuts on the body surface or appendages (Figure 

Like manatees, dolphins and porpoises are 27). It is usually possible to visualize the course 

sometimes killed or injured from collisions with 

small vessels. In Sarasota, Florida, for example, 

researchers have documented six cases of injury 

to bottlenose dolphins resulting from collisions 

with boats from 1983 to 1997 (Wells and Scott, 

1997). Five of these animals survived their 

injuries, but bear scars from the encounters; one 

calf disappeared after a collision and is believed 

to have died (R. Wells, Chicago Zoological 

Society, personal communication; Figure 26). 

Figure 27. Healing wounds from a boat propeller on 

the dorsal fin of a bottlenose dolphin from Sarasota, 

FL. Note the parallel and evenly spaced cuts on the 

fin. The photograph was taken in 1983 shortly after 

the encounter; the dolphin was still alive, although 

disfigured, in 1998. Photo courtesy of R.S. Wells, 

Chicago Zoological Society. 

of the propeller blades over the body of a dolphin 

or porpoise. The lacerations may be deep, sometimes penetrating completely through the dorsal 

Figure 26. Healing wounds from a boat propeller on the 

dorsal surface of a bottlenose dolphin from Sarasota, FL. 

The dolphin survived the encounter. Photo courtesy of 

R.S. Wells, Chicago Zoological Society. 

There are two distinct types of gross evidence associated with collisions with small vessels: blunt trauma from the impact itself and lacerations from the propeller. Either or both may be 

present, depending on the nature of the collision. 

Evidence of blunt trauma and lacerations from 

propellers are typically found on the dorsal surface of the animal and often involve the dorsal fin. 

Evidence of blunt trauma may consist of hemorrhage, occasionally massive or diffuse, around the 

point of impact. In severe cases, broken bones, 

ruptured organs, and torn underlying tissue may 

accompany the hemorrhage. The hemorrhage 

may not be visible externally, so be sure to conduct a full internal examination to look for evidence of blunt trauma. Wounds from propellers 

are usually obvious and distinctive. Lacerations 

fin (wells and Scott, 1997). 

If the animal survives the initial collision, 

lacerations may be in the process of healing and 

may be infected. It is important to distinguish 

these cases from those in which the animal was 

killed outright from the collision; so take detailed 

notes, obtain photographs and, most importantly, 

retain samples for histopathological analysis (see 

Geraci and Lounsbury, 1993). Histopathology 

samples will allow determination of whether the 

impact occurred ante- or post-mortem, as boats 

occasionally strike the floating carcass of a dolphin or porpoise. In post-mortem collisions, the 

propeller marks may be on the ventral or lateral 

surfaces. As noted above, many dolphins survive 

collisions with boats and exhibit healed scars 

from these adverse encounters. Obviously, it is 

important to distinguish such cases from those 

with recent wounds that may have contributed to 

the death of an animal. 
3.3 Blast-Induced Trauma 

Only scattered observations exist regarding 

the effects of blast-induced trauma on marine 

mammals. The most detailed observations of 

blast injuries have been made with large whales 

(Ketten, 1995). Direct observations are lacking, 

but it is likely that explosions can cause both 

acoustic and percussive trauma in small 

cetaceans, as they do in other marine mammals. 

This trauma is caused by rapid and massive pressure changes brought about by the shock wave 

from the explosion. The degree of tissue damage 

will vary with the size and distance from the 

blast, in addition to other factors (Ketten, 1995). 

Lethal injury from such explosions may be very 

difficult to detect, particularly for non-specialists, 

as much of the trauma may occur within the ear. 

Fractures of the periotic bone have been reported 

from humpback whales exposed to explosive 

blasts, but much of the other trauma exhibited by 

these whales would not be readily apparent in a 

routine necropsy. Therefore, we recommend that, 

if blast injury is suspected as a probable cause of 

death of a dolphin or porpoise, the entire head 

should be retained and examined by a specialist 

with experience in assessment of blast injury. 

4.0 EXAMINING A SMALL CETACEAN 

FOR EVIDENCE OF HUMAN INTERACTION 

As noted in the field guide to strandings by 

Geraci and Lounsbury (1993), information has 

scientific value only when carefully documented. 

For this reason, it is recommended that a standard 

data form, which prompts observers to check for 

each category of physical evidence, be used to 

record information. We present here the data 

form we use to score gross evidence of human 

interaction in our field examinations. Other standard data (sex, length, body mass, morphometrics 

etc.) should be recorded on appropriate data 

sheets. This protocol was first developed by 

Haley and Read (1993) and refined herein. Other 

useful advice on conducting post-mortem examinations of small cetaceans may be found in 

Geraci and Lounsbury (1993) and Jefferson et al. 

(1994). Helpful information may also be found in 

similar manuals designed for use with other 

species of marine mammals (Bonde et al., 1983; 

Dierauf, 1994; Hare and Mead, 1987). 

Whenever possible, examinations should be 

performed on carcasses that have not been frozen. 

Freezing and thawing carcasses may introduce 

artificial marks, cracks, or damage to appendages 

and lead to improper identification of an interaction such as entanglement. In addition, freezer 

breakdowns may completely destroy important 

evidence. Therefore, it is preferable to conduct 

this examination on a fresh carcass as soon as 

possible after discovery, even if a full necropsy is 

not to be conducted immediately. 
4.1 General Information 4.2 External Examination 

Follow the general procedures for recording 

data described by Geraci and Lounsbury (1993). 

Record the field number, species, sex, length, 

cause of death (if known), date of death (if 

known), date and location of the examination, 

stranding location and name of the examiner. It is 

critical to take video footage and/or photographs 

of the whole animal and of any unusual marks or 

lesions (Figure 28) and note this on the data sheet. 

Extreme care should be taken with photo-docuFigure 28. An example of a good field photograph. 

The lighting, exposure and composition are appropriate and the field number, location and date are clearly 

visible. The caudal peduncle of this bottlenose dolphin, stranded in North Carolina, has been clearly 

severed. Photo courtesy of Andrew Westgate, Duke 

University Marine Lab. 

mentation; avoid poor lighting, exposure, and 

composition. Ensure that the field number is visible in each photograph and at some point in the 

video footage. It is often useful to have someone 

provide an audio narrative on the videotape 

describing particular lesions, marks or other features of interest. Any other relevant information 

should also be recorded at this time. The condition of the carcass should be evaluated using the 

Smithsonian Institution criteria: Code 1 = live; 

Code 2 = good condition (freshledible); Code 3 = 

fair condition (decomposed, but organs intact); 

Code 4 = poor condition (advanced decomposition); Code 5 = mummified or skeletal remains 

(Geraci and Lounsbury, 1993). Useful information can be obtained from Codes l B 3, and occasionally even from Code 4 specimens. Any additional comments can also be included at this time. 

4.2.1 Body Condition 

On the data sheet, denote the animal as 

"emaciated" or "not emaciated." An emaciated 

animal is in poor nutritional condition with a thin 

blubber layer, sunken cervical region posterior to 

the skull, and atrophied epaxial musculature 

(Kuiken, 1996). Animals in good nutritional condition have a relatively thick blubber layer and 

well-developed musculature. The relative thickness of the blubber in robust specimens will obviously vary from species to species and even from 

season to season within a species. The apparent 

condition of a carcass may also change with 

decomposition; very degraded carcasses can 

sometimes appear emaciated after the blubber has 

rendered. The body condition of animals in 

advanced states of decomposition (Codes 3+) or 

those in which the body condition of the animal 

cannot be assessed should be recorded as "CBD" 

(cannot be determined). We find this general 

assessment of body condition to be useful in distinguishing between animals that died of chronic 

health problems and those that died of acute causes. 

4.2.2 Net or Line Marks 

Thoroughly examine the entire body for 

unusual marks, such as those from lines or nets. 

Be sure to examine both sides of the carcass and 

the dorsal and ventral sides of all appendages. As 

described in detail above, lesions from monofilament gill nets appear as thin, distinct indentations 

on the skin of the animal that occasionally penetrate through the dermis. Multifilament net and 

lines often leave an impression of the braided 

material in the skin. Describe each mark in detail 

and be sure to obtain good photographs of each 

lesion. After discovery, carcasses are often 

secured by line or rope, which may leave impressions in the skin. If this is the case, be sure to 

note on the data sheet that these impressions 

occurred after discovery. The same also holds for 

numbered tail tags attached by NMFS observers. 
4.2.3 Fishing Gear Present and Retained 

If fishing gear or other objects are attached to 

the carcass photograph then remove and retain a representative sample and note this clearly on the data 

sheet. It is often possible to identify the fishery 

responsible for an entangled marine mammal from 

only a fragment of net or line. Note where and under 

whose supervision such materials are retained. 

subcutaneous hemorrhage on the exterior of the 

body B these areas will appear purplish, red 

and/or swollen. Measure the size of the hemorrhage in three dimensions. Carefully examine the 

tissue and muscles beneath any external hemorrhage during the interior examination, and 

remember to check for the presence of broken 

bones. In some cases, even massive blunt trauma 

may not be evident externally, so be sure to conduct a thorough internal examination. 

4.2.4 Penetrating Wounds 

4.2.7 Scavenger Damage 

Carefully examine the body for any penetrating wounds, caused by gunshots, gaffs, or other 

equipment (e.g., temperature probes). Describe the 

size, depth, and location of all wounds. Follow the 

path of the wound into the superficial tissue and 

obtain samples for histopathology to determine 

whether the wound occurred ante- or post-mortem 

(Geraci and Lounsbury, 1993). The remains of a 

bullet or shot can often be found internally within 

the vicinity of the gunshot wound. 

4.2.5 Mutilation 

Note any missing appendages or any other 

signs of mutilation, such as cuts or slits into the 

body cavity. Human removal of appendages can 

be distinguished from advanced decomposition, 

predation or scavenging by the clean, smooth surfaces left by knife cuts. Appendages or the body 

surface may also be severed or damaged from 

collisions with boat propellers. If a series of parallel cuts have been made into the skin, measure 

the distance between the cuts and take a photograph of the region. Ante-mortem wounds are 

associated with hemorrhage; post-mortem 

wounds are usually blanched and not associated 

with hemorrhage. Ante- and post-mortem 

wounds can be readily differentiated by 

histopathological analysis. 

Record all areas on the external surface of 

the carcass where scavenger damage is apparent. 

This will help to describe the overall condition 

and appearance of the carcass. Carcasses of small 

cetaceans taken in bottom-set gill nets may sustain damage from benthic scavengers such as 

amphipods and hagfish while they are entangled 

in the net. Carefully examine circular holes in the 

animal, particularly if they appear to extend deep 

into the internal cavity of the carcass, to ensure 

that they are not gunshot wounds. Gulls cause the 

most common type of scavenger damage found 

on stranded small cetaceans. Gull pecks typically occur on areas of the carcass exposed on the 

beach or while afloat and appear as multiple, 

shallow scrapes into the skin or appendages. 

Gulls will often preferentially scavenge around 

the lower jaws to obtain access to the lipid-rich 

mandibular fat pads (Figure 29). 

A hemorrhage is the escape of blood from Figure 29. Damage caused by gulls scavenging 

ruptured vessels, which is often caused by trauma around the left lower jaw of a harbor porpoise strand 

(Bonde et al., 1983; Kuiken, 1996). Note any ed in Virginia. Note the exposed mandible. 
4.3 Internal Examination 4.3.3 Lung Contents 

Follow the general recommendations for 

internal examinations laid out in Geraci and 

Lounsbury (1993) and Jefferson et al. (1994). 

Our protocol is compatible with most internal 

examinations conducted on small cetacean carcasses, but care should be taken to record all pertinent information on the data sheet as the 

necropsy progresses. 

4.3.1 Sub-Dermal Hemorrhaging 

Carefully strip the blubber from the entire 

carcass and examine the underlying muscles and 

tissue for any inflammation and reddening. Pay 

particular attention to the cervical region as this 

area is often characterized by hemorrhage in 

entangled specimens. The size and location of all 

hemorrhages should be recorded and photographed. Focal hemorrhages are indicative of 

blunt trauma. Attempt to match any sub-dermal 

hemorrhage with evidence of external trauma in 

the overlying tissue. It is important to distinguish 

ante- and post-mortem trauma, as the former may 

be associated with the cause of death but the latter is not. Ante-mortem hemorrhage is characterized by infiltration of blood and fluid from ruptured vessels into surrounding tissue and is often 

accompanied by swelling. In post-mortem trauma, there is no infiltration or swelling, but pockets of coagulated blood may be present. 

4.3.2 Broken Bones 

Describe any fractures and disarticulated 

joints. Pay particular attention to the ribs and 

skull, where fractures often occur, particularly in 

the smallest cetaceans. Make a careful evaluation 

and description of any broken bones, as bones can 

be broken during post-mortem handling. Look 

for any signs of healing in a fracture, such as 

fibrous connections between bone fragments, that 

might indicate that the trauma was not of a recent 

origin. Recent ante-mortem fractures are always 

associated with hemorrhage. 

Open the trachea and main bronchi in each 

lung and describe the contents (froth, fluid, or 

air). Froth may be white, yellow, or blood-tinged. 

Fluid and froth are often found together. Death 

by hypoxia is often associated with edematous 

lungs that appear wet and heavy. 

4.3.4 Stomach Contents 

A full stomach, containing partially digested 

prey, may be indicative of an animal that was in 

good health and died a traumatic death. It is useful, therefore, to excise the stomach and make a 

careful examination of the contents after the 

necropsy is completed. The general cetacean 

stomach complex consists of three compartments: 

the forestomach, main stomach, and pyloric 

stomach. The forestomach is an enlargement of 

the esophagus, with no definitive demarcation 

between the two structures. In contrast, narrow 

passages separate the fore from the main stomach, the main from the pyloric stomach, and the 

pyloric from the duodenal ampulla. Beaked 

whales differ from other cetaceans in that they 

lack a forestomach and have up to I1 "connecting 

chambers" between the main and pyloric stomachs (Mead, 1993). Tie off tightly both the 

esophageal and duodenal ends with a string or 

cable before removing the stomach complex. As 

much of the esophagus should be taken as possible, since animals that die traumatically sometimes vomit and food items may still be lodged 

therein. The duodenum should be pinched and 

tied 10-cm posterior to the pyloric sphincter 

(Jefferson et al., 1994). After the necropsy has 

been completed, weigh the entire stomach complex in the laboratory and open each compartment individually, starting with the 

esophagus/forestomach and working toward the 

pyloric stomach. Usually, most of the intact prey 

remains are found in the forestomach. Intact 

remains should be removed immediately and 

frozen. Look carefully for any foreign objects 

that may be lodged in the stomach or esophagus. 

After the intact prey have been removed, the 
stomach compartment should be everted and gently rinsed in water to dislodge all remaining prey 

parts. A sieve or strainer should be used during 

the rinsing to collect small prey remains and foreign objects. Otoliths and other bones should be 

stored dry, cephalopod beaks can be placed in 

70% ethanol, and parasites should be fixed in an 

appropriate solution (Dierauf, 1994). Weigh the 

entire stomach complex again after all contents 

have been removed. 

4.3.5 Histopathology Samples 

Examination of histological samples by an 

experienced pathologist is an essential component of post-mortem examinations of stranded 

marine mammals. When possible, samples 

should be taken from a fresh carcass, but samples 

from a frozen carcass may still be useful. 

Abnormal and adjacent normal tissues should 

both be sampled, because the diagnosis of condition often occurs at this interface. The optimal 

size tissue sample to yield the best fixation is 1 

cm3, though larger samples can be taken if adequate fixation is supplied. The ratio of formalin 

(10% solution) to tissues in the container, preferably a plastic jar with a screw-top closure, should 

be at least 10:l (i.e., 10 parts formalin to 1 part 

tissue (Dierauf, 1994). Multiple samples can be 

placed in the same jar. All major organs including brain, lung, heart, spleen, liver, kidney, adrenal gland, lymph nodes and urinary bladder 

should be sampled. Also sample all areas of hemorrhage, fracture, blunt trauma, infection, and any 

regions of unusual pathology. Label the 

histopathology jar with the animal=s field number, species, date, and fixative contents, using a 

permanent ink marker. 

4.3.6 Gross Pathology 

All major organs should be examined for the 

presence of parasites or other lesions. Examine 

ducts and lumens of each organ, as parasites are 

most often found in these areas. Note the type, 

quantity, and location of the parasites present. If 

necessary, cut around the area with the parasite 

and preserve in an appropriate fixative (Jefferson 

et al., 1994; see Dierauf, 1994, for more specific 

collection, preparation, and preservation of tissues with parasites). Also note any organs which 

are enlarged or reduced, and unusual lesions in 

the interior or exterior of the animal. 

4.4 Diagnosis 

Diagnosis of the cause of death of any 

stranded small cetacean requires the completion 

of a pathology report and consultation with a veterinary pathologist. Nevertheless, we consider 

several types of gross evidence to be diagnostic of 

various anthropogenic causes of death in these 

animals, as outlined above. Other lines of evidence are consistent with, but not diagnostic of, 

traumatic death from human activities. 

Mutilation, for example, can occasionally occur 

Figure 30. Post-mortem mutilation on a bottlenose 

dolphin stranded in North Carolina. Strips of skin 

and blubber had been removed by a bystander to feed 

gulls, prior to the response of stranding network personnel. 

on the beach and thus is not diagnostic of traumatic death at sea (Figure 30). Personnel conducting the post-mortem examination should be 

conservative in their evaluation and diagnosis. It 

is our experience that, in the vast majority of postmortem examinations, it is not possible to assign 

a cause of death, even when the specimen is fresh. 

Nevertheless, with care, it is often possible to 

identify cases in which animals have died as a 

result of adverse interactions with humans. 
5.0 EVALUATION OF HUMAN INTERACTIONS WITH SMALL CETACEANS 

1. GENERAL INFORMATION 

Field No. Species 

Sex Length Examiners 

Cause of Death (If known) Date of Death (If known) 

Location of Exam Date of Exam 

Video (Tape Number) Photos (Roll and Frame Nos.) 

Condition: SI Code: 1 2 3 4 5 Fresh or Frozen 

Comments: 

2. EXTERNAL EXAMINATION 

A. BODY CONDITION: Emaciated specimens often exhibit sunken epaxial musculature and a neck 

EMACIATED NOT EMACIATED CBD N/E - 

B. NET OR LINE MARKS: Indicate Y/N/CBD/NE for each area and carefully describe net or line marks: 

HEAD D. FIN FLUKES L. FLIPPER R. FLIPPER PEDUNCLE 

OTHER 

C. FISHING GEAR PRESENT ON ANIMAL D. GEAR RETAINED 

YES NO YES NO 

E. PENETRATING WOUNDS: YES NO - CBD N/E - 

Describe bullet wounds, gaff marks, punctures, etc: 

F. MUTILATION: Body Slit or Mutilated? YES NO - CBD N/E - 

Appendages Removed? YES NO - CBD WE - 

Describe cuts, slashes, slits in body wall, missing appendages, etc: 

G. HEMORRHAGING/BRUISING: YES NO - CBD N/E - 

Describe extent and area: 

H. SCAVENGER DAMAGE: YES NO - CBD N/E - 

Describe extent and area: 
HUMAN INTERACTION PROTOCOL Page 2 Field No. 

3. INTERNAL EXAMINATION 

A. SUB-DERMAL HEMORRHAGING: YES NO - CBD WE - 

Describe extent and area: 

B. BROKEN BONES: 

Describe: 

YES NO - CBD - 

C. LUNGS & BRONCHI CONTENTS: AIR FLUID FROTH CBD - 

Describe appearance of lungs (heavy, consolidated, etc.) and contents of respiratory tract: 

D. STOMACH CONTENTS: PRESENT ABSENT 

RETAINED: YES NO - 

E. HISTOPATHOLOGY SAMPLES RETAINED: YES NO - 

F. GROSS PATHOLOGY: YES NO - CBD Nil3 - 

Describe: 

4. DIAGNOSIS: 

Indicate initial diagnosis; a final diagnosis should be made after all test results are completed. 
6.0 ACKNOWLEDGMENTS 

We owe a special debt of gratitude to many colleagues who have been instrumental in developing this 

protocol and who have offered advice and encouragement. In particular, we would like to thank Per 

Berggren, Bob Bonde, Patrik Borjesson, Rose Borkowski, Ana-Maria Botero, Tara Cox, Greg Early, 

Ruth Ewing, Damon Gannon, Frances Gulland, Nancy Haley, Dave Johnston, Darlene Ketten, Heather 

Koopman, Thijs Kuiken, Thomas Lipscomb, Blair Mase, Bill McLellan, Wayne McFee, Laurie 

Murison, Aleksija Neimanis, John Nicolas, Ann Pabst, Charley Potter, David Potter, Butch Rommel, 

Teri Rowles, Jeff Skelton, C.J. Sylvester, Vicky Thayer, Krystal Tolley, Katie Touhey, Mike Tork, 

Randy Wells and Andrew Westgate. John Wang was instrumental in starting this project and we 

acknowledge his contribution and dedication with gratitude. Thanks are due to the members of the 

Northeast and Southeast stranding networks who provided assistance and specimens. We are also 

grateful to observers from Manomet Bird Observatory, the Department of Fisheries and Oceans and the 

Grand Manan Whale and Seabird Research Station for retrieving carcasses from gill net vessels and 

herring weirs. We owe a special debt of gratitude to the fishermen who were receptive to our research 

endeavors. This report was improved by the comments of Damon Gannon, Heather Koopman, Bill 

McLellan, Jim Mead, Ann Pabst, Randy Wells, Andrew Westgate, and several anonymous reviewers. 

Finally, we would like to acknowledge Dean Wilkinson and Teri Rowles, who made this work possible 

through NMFS Reference Order 43AANF501263 from the NMFS Office of Protected Resources. 
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