NMFS DECIDES WHETHER VASHON CALF SHOULD BE CAPTURED OR LEFT ALONE
On February 22, 2002, the National Marine Fisheries Service (NMFS) convened a scientific advisory panel to seek professional opinions on a list of questions regarding the unusual occurrence of a solitary juvenile killer whale in central Puget Sound. Following a discussion of the available data, panel participants were polled for their opinions. NMFS staff then summarized the opinions received into the following list of responses to the questions. The responses are being used in the development of possible intervention options for the welfare of the animal under Section 109 of the Marine Mammal Protection Act.
The juvenile whale, thought to be a female based on observations of external morphology, was first discovered by a local researcher on January 14, 2002, in central Puget Sound near the Fauntleroy/Vashon Island ferry route. Photographs were taken and compared with the photo identification catalogue of the Southern Resident Community with no matches found. Audio recordings of the whale's calls were made by local researchers and analyzed by researchers in the U.S. and Canada who agreed the calls are an acoustic match for a pattern (dialect) known in the Northern Resident Community. Further analysis of photographs yielded a possible match with photos from the Northern Resident Community. The identification of the animal as A73 was later confirmed by a match with photographs taken of Northern Resident whales in Southeast Alaska. Further analysis and matching to archived genetic data in Canada is being done. Assuming confirmation via the genetics analysis the whale has been identified as a calf of Northern Resident female A45 from the 2000 season. A45 was not observed during the 2001 census, is missing and presumed dead. The calf was subsequently seen by Canadian researchers during the 2001 season in the company of another female belonging to a different pod and in a different acoustic clan.
Orphaned calves usually accompany siblings but may occasionally accompany surrogates for a time following the disappearance of the mother and sometimes females nearing reproductive age will temporarily "adopt" or "babysit" calves from other females. However, there is no documented evidence of calves leaving their natal pod and subsequently rejoining the pod or successfully being accepted as a member of another pod.
Observations made by two independent veterinarians, who visited the animal in late January and early February, indicate that the whale is underweight and is exhibiting the skin lesions described as whale pox (a common affliction). The animal is believed to be feeding based on observed defecation and sightings of predation events. Members of the public reportedly observed a predation event and collected scraps of fish at the scene, which were subsequently given to NMFS for identification. In general the animal appears to be bright, alert and responsive at this time. Veterinarians report however, that the whale's breath has a ketone (alcohol like) aroma indicating that it may not be consuming sufficient prey to maintain itself over time and is metabolizing its own fat reserves at some rate or is consuming some novel prey items that may contribute to the odor. Sample collections and analysis of respiratory gases will be attempted to confirm these observations.
Consultation on the Questions:
Based on the veterinary field observations, observed behavior, age and what is known of the animals history, NMFS polled the panel participants for their opinions on the following questions.
1. What is your assessment of this animal's current health (medical/behavioral), and what additional diagnostic information is necessary to make a more informed assessment?
Group Response: In general, the group expressed the opinion that the current condition of the animal is poor and that the prognosis for the future is also poor. The length of time for the deterioration of the animals health to become acute can not be predicted but several participants indicated that the observed condition is likely a downward spiral. Time estimates for the duration of the deteriorating condition, when offered ranged from weeks to months. The group suggested additional data collection through longer observation sessions to determine levels of feeding. The use of tags or a "crittercam" for data collection was also suggested. Most of the outstanding medical questions would likely require handling of the whale.
2. What is the probability of it surviving and/or reuniting with other killer whales if current conditions continue? (Consider the potential for habituation to humans.)
Group Response: The group expressed the opinion that the likelihood for long- term survival is low and that the animal is unlikely to reunite with its pod or join a surrogate. Among the reasons given for pessimism were observations that; a) the animal did not join up with Southern Residents when they passed the area; b) early observations, during the live capture era, of individual animals left behind when their respective matrilines were removed, indicate that reuniting or joining a pod is unlikely; c) body condition needs to improve to ensure viability and the age of the animal makes it unlikely that it has sufficient skills to find foraging areas; d) Northern Residents do not frequent the Sound and the animal shows no sign of moving back to its normal range; and e) the animal formed a temporary association with another pod but subsequently separated.. There is no historic, behavioral or genetic evidence for resident calves leaving a pod then rejoining to it later or for joining a new pod and thriving.
3. What is probability for the long-term survival of this animal if short-term, moderate intervention is used?
Group Response: The group was mixed in its opinion on whether moderate or "in situ" intervention would enhance long-term survival. Some expressed concern that short-term feeding may produce behavioral dependence while others suggested that the animal's current condition did not mean irreversible decline and that feeding could help. Unless intensive efforts are made to reduce the tendency for habituation, there is a strong possibility that the whale could be "fattened up" but this would only restart the downward curve and the problems of reuniting the animal with its pod would still exist. The possibility that an "all or nothing" approach would be needed was introduced.
4. What are the risks/benefits of capturing this animal?
Group Response: The group expressed the belief that capture could be accomplished with relatively low risk to the animal, provided a good strategy and people are used. The risk of capture may be outweighed by the low expectation for survival. Some cautions were made that the timing of capture be considered because the animal's condition is declining and risk could go up. The risk associated with transporting the animal will likely compound the risk of capture.
5. If rehabilitation is attempted what needs to be done to minimize potential dependency on humans without compromising the health of the animal?
Group Response: The group expressed support for the concept of minimizing potential dependency such as reducing "dead fish diet" and there have been some successful re-introductions of odontocetes but no real suite of procedures were offered to eliminate the animal's dependency on people at the far end of rehabilitation.
6. Would rehabilitation and release likely change the probability of it surviving and/or reuniting with other killer whales if current conditions continue?
Group Response: The group was mixed in its opinion on whether rehabilitation would improve the probability of survival. However, the general "feel" was that the probability for survival under current conditions is so low that rehabilitation is unlikely to make it lower, i.e., net effect of rehabilitation may be positive but habituation and dependency are major issues.
7. In addition to the current releasability criteria, what additional factors should be used to determine whether this animal is releasable following rehabilitation?
Group Response: The group recognized the international implications of this trans-boundary stock . In addition, it was recommended that timing a release to coincide with local prey abundance and availability of con-specifics from the natal pod are important considerations. One participant emphasized that answering the questions posed by the release criteria before intervention is initiated would be a valuable way to gauge the likely success of an intervention effort.
Teri Rowles, DVM, NMFS, Marine Mammal Health & Stranding Response
Lance Barret-Lennard, Vancouver Aquarium
David Huff, DVM, Vancouver Aquarium
Dr. Marilyn Dahlheim, National Marine Mammal Laboratory (NMML)
Graeme Ellis, Dept. of Fisheries & Oceans, Canada
Dr. John Ford, Dept. of Fisheries & Oceans, Canada
Dr. Dave Bain, University of Washington
Bill Walker, NMML, Consultant
Frances Gulland, DVM, The California Marine Mammal Center
Jim McBain, DVM, Busch Entertainment
Steve Jeffries, Washington Department of Fish & Wildlife
Dr. Brad Hanson, NMML
Dr. Steve Kalinowski, Northwest Fisheries Science Center
Invited but Not Present for the Discussion:
Ken Balcomb, Center for Whale Research
Jeff Foster, Consultant
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