Return-path: <WHE_WILLIAM@FLO.ORG> Received: from FLO.ORG by VMSVAX.SIMMONS.EDU (PMDF V4.3-10 #8767) id <01HNMRQD2WR4003ZUE@VMSVAX.SIMMONS.EDU>; Wed, 01 Mar 1995 18:59:26 -0500 (EST) Date: Wed, 01 Mar 1995 18:57:18 -0500 (EST) From: Michael Williamson <WHE_WILLIAM@FLO.ORG> Subject: Info: Paper on Ocra Rescue, Barnes Lake, AK To: whalenet@VMSVAX.SIMMONS.EDU Message-id: <950301185718.4029@FLO.ORG> Content-transfer-encoding: 7BIT From: SMTP%"MARMAM@UVVM.BITNET" 1-MAR-1995 16:40:38.30 To: WHE_WILLIAM CC: Subj: Nine page summary of Barnes Lake, AK, killer whale rescue Date: Tue, 28 Feb 1995 16:24:10 -0800 Reply-To: Marine Mammals Research and Conservation Discussion <MARMAM@UVVM.BITNET> Sender: Marine Mammals Research and Conservation Discussion <MARMAM@UVVM.BITNET> Comments: Warning -- original Sender: tag was rbaird@SOL.UVIC.CA From: David Bain <firstname.lastname@example.org> Subject: Nine page summary of Barnes Lake, AK, killer whale rescue X-To: MARMAM%UVVM.BITNET@vm1.nodak.edu To: Multiple recipients of list MARMAM <MARMAM@UVVM.BITNET> The following is a preliminary report on the entrapment and intervention to aid killer whales in Barnes Lake, Alaska, in 1994. A formal report to be submitted for publication is planned when data analysis has been completed. KILLER WHALES (ORCINUS ORCA) IN BARNES LAKE, ALASKA: A PRELIMINARY REPORT David E. Bain Marine World Foundation Vallejo, CA 94589 February 28, 1994 INTRODUCTION I received a report that a group of killer whales (Orcinus orca) was in Barnes Lake, Alaska, from Russ Cameron of Peregrine Productions of Beaverton, OR. His report raised two bases for concern. First, the lake contained significant amounts of fresh water, which might be harmful to killer whales after long-term exposure. Second, due to the small size of the lake, the food supply might be limiting. Mitigating these concerns were the addition to the lake of approximately one-third its volume of sea water at each high tide, and salmon migrating into Sweetwater Lake just upstream of Barnes Lake. The whales had apparently entered the lake on their own, and hence should have been able to exit the lake on their own. However, killer whales can be confined by psychological barriers, such as nets or low walls, which they are physically able to cross. These concerns raised the possibility that human intervention in the situation could promote the welfare of the whales. To help determine whether intervention would promote their welfare, and what kind of intervention might be appropriate, NMML granted my request to become a designated agent under its marine mammal permit, No. 791. Whether intervention was the appropriate action versus allowing nature to take its course is beyond the scope of this report. Prior to my departure for Barnes Lake, I made a number of phone calls to assess the situation. Descriptions of the group ranged from seven individuals including one bull, to ten individuals including 4 bulls. Reported dates of entry into the lake ranged from mid-July to mid-August. Salmon runs typically persist into the middle of September, although the runs apparently ended early this year, with only small numbers of fish entering Barnes Lake after the 23rd of August. Although U. S. Coast Pilot reports that there is sufficient depth for killer whales to exit the lake at high tide, people living in the area indicated current was a limiting factor, and that there was a short time window around high slack that they felt safe entering and leaving the lake. There were also reports that harbor seals had used the lake in significant numbers prior to the whales' arrival, but had been scarce since. There was one report of the whales actively chasing fish during the first half of September. One fishing guide indicated he had used the lake for nine years and that this was the first time he had seen killer whales there. Outside the lake, NMML has been conducting surveys and has sighted killer whales fairly regularly. Local residents also reported sightings of killer whales outside the lake, with whales feeding on fish on some occasions and marine mammals on others. Although whales had been sighted outside the lake subsequent to reported dates of entry, there were no reports of killer whales not being in the lake once it became common knowledge that whales had been sighted there. The Barnes Lake area may be used by killer whales described as members of the Northern Resident Community, Offshore Community, Transient Community, and other whales previously sighted in Alaskan waters. With these thoughts in mind, I departed for the area. OBSERVATIONS I flew over Barnes Lake on Sunday, October 2, 1994. One whale was dead-stranded on a small island. Other whales were still swimming in the lake. The altitude of the observation (>2000') did not allow assessment of the condition of the live animals. On Monday, October 3, I entered the lake in a small boat. Lighting was poor, and the whales did not allow close approaches. However, the observations reported below indicated the remaining whales were in poor to fair condition. On Tuesday, October 4, no effort was made to enter the lake due to a tsunami warning. On Wednesday, October 5, I was joined by Linda Shaw of NMFS, and Jim Antrim and Bill Winhall of Sea World to aid in assessment of the situation and to gather information important to the consideration of options for intervention. Lighting was better on this day allowing a more thorough assessment of the condition of the whales. GROUP COMPOSITION The original group appeared to consist of nine whales: one adult male, one adolescent male, four adult female sized animals, one large juvenile (est. age = 6-8 yr), one small juvenile (est. age = 2-4 yr) and one calf (est. age = 0-2 yr). By the time I arrived, one adult female had died. The subadult male was only seen alive on October 3, and was found dead on Friday, October 7. A preliminary review of photographs indicates that the whales are part of the "offshore" community. One has been tentatively identified as AP1, a female sighted in Icy Strait in 1989 by Dena Matkin. A second was tentatively identified as O55, sighted in 1992 off Langara Pt. in the Queen Charlotte Islands (G. Ellis, Pacific Biological Station, pers. comm.). BEHAVIOR The whales moved very slowly, generally singly, though occasionally in pairs, and rarely as a three-some. Saddles were not raised out of the water, except by the young juveniles. At least one whale listed slightly to the side on some surfacings. On some occasions, the dorsal fin was not completely submerged between breaths. Respiratory intervals tended to be long and relatively uniform. Breathing sounded slightly less forceful and crisp than normal. Echolocation clicks were heard, but calls were not (though the time spent monitoring acoustic behavior was short). No observations of successful or presumed prey capture were made. The orcas showed no interest in a harbor seal that inhabited the lake. These abnormalities cannot be attributed to the limited size of the lake. Killer whales in aquaria of comparable depth and smaller surface area exhibit behavior much more similar to that of free ranging killer whales than that observed in Barnes Lake. In contrast to the observed behavior, groups of three or four are common, and it would not be uncommon for all animals to travel together. Saddles are normally raised out of the water on most breaths. Dorsal fins are normally kept vertical, except during play and foraging. Partial submergence of the dorsal fin is only normal during deep rest for males, and other whales during active foraging. Respiratory intervals are normally bi-modal, with a series of short intervals followed by a long interval. PHYSICAL CONDITION The skin of some whales showed large areas of gray discoloration. The skin had a "matte" finish, rather than the normal glossy appearance. Observations of the dead male indicated the gray areas were due to sloughing of large patches of skin, in contrast to the small flakes that are normally sloughed. The matte appearance was apparently due to the failure to slough skin. Slight depressions were observed behind the blowholes of some whales (most were not approached closely enough to make this determination). The dead whale appeared thin along the back, and the outline of the rib cage was visible. Such observations would not have been possible with the live whales as they did not raise their backs or ribs out of the water, and the dark color of the water (perhaps due to dissolved organic matter) prevented underwater observation. The dorsal fins were erect, except for small bends which were well within the range of healthy animals. POTENTIAL FOR UNASSISTED DEPARTURE The orcas remained in the deep portion of the lake. They did not explore the channels leading to open water, or use the shallow fringes of the lake. Strong currents (estimated at 8 knots 2 hours prior to high tide) flowing into the lake during the rising tide lent support to the idea that current contributed to the whales unwillingness or inability to leave lake even when there was sufficient depth. Thus it seemed unlikely that they would leave the lake on their own. POPULATION DENSITY Barnes Lake has a surface area of approximately 2.5 sq. km. Thus the population density ranged from about 3.6 / sq. km to 2.8 / sq. km. For comparison, the smallest day range I have observed in over 500 days of observation wild killer whales is approximately 25 sq. km (for daylight periods up to two consecutive days). The highest population density I have observed is about 0.4 whale per sq. km of day range. These observations were in core areas at times believed to correspond to periods of peak food availability. Observations during times of limited food availability indicate day ranges may exceed 500 sq. km, with population densities of .01 whales / sq. km of day range. INTERPRETATION I interpreted the observations as follows. The whales showed subtle signs of being in poor condition. The population density was far in excess of what was sustainable. The lake was not part of normal killer whale habitat. The orcas were unlikely to leave the lake on their own, even if their physical condition deteriorated. In the absence of subsequent observations to the contrary, it likely would be in the interest of the whales to be relocated to open water. Given that one whale had died and that the condition of the others was likely to deteriorate rather than improve, intervention as soon as possible was likely to be more helpful than waiting for obvious signs of distress. With this interpretation in hand, my authority under the NMML permit was rescinded, and control of the situation was placed clearly in the hands of the Alaska Region's stranding coordinator, Linda Shaw. INTERVENTION A decision was made to intervene with the following concerns. Intervention would not promote the welfare of the animals if it resulted in: A) movement into Sweetwater Lake, B) stranding on a beach, or C) separation of the two youngest animals from the bulk of the group. Intervention was to take the form of small boats driving the orcas through Indian Creek towards open water by their occupants banging on hollow, metal pipes. To prevent outcome (A), two boats were stationed at the entrance to Sweetwater Lake. To reduce the probability of outcome (B), the drive began with boats far away from the whales, and behavior was continuously monitored for signs of panic that might lead to stranding. To mitigate outcome (B) if it occurred, personnel with experience handling killer whales and stranded marine mammals were recruited from Marine World / Africa USA, Sea World, and the California Marine Mammal Center. To prevent outcome (C), the whales were continuously monitored. We were also concerned about the safety of the human participants. The U.S. Coast Guard was notified that the drive would take place. The Forest Service was notified, and arrangements were made to use their cabin in case people were unable to leave the lake (due to tidal conditions or engine failure). Potential threat displays from the orcas were discussed, and appropriate responses determined. A goal was set of having ten boats participate, which would result in a maximum spacing of ten boats per mile. In the event, 13 boats were recruited. Ten of these boats were assigned routes, while the remaining three were positioned as necessary. One boat not banging pipes was used to try to finely adjust the movement of the whales. In addition to the three major concerns, some minor problems were anticipated. First, there was uncertainty in the time the drive would take. (Timing was critical because human access to the lake was limited to a few hours, and the time at which the exit was likely to be passable for the orcas was believed to be much shorter.) The drive was scheduled as early as possible (based on tidal limitations to access to the lake), but that might have resulted in the whales reaching the rapids while they were impassable. Thus a holding area was identified that had a relatively narrow opening back into the lake, but provided the orcas space to remain a comfortable distance from the banging pipes. This narrow opening was also designated a position for a safety line in case the whales evaded the main drive line. In the event, the holding area was used while waiting for the current to slacken, but the safety line was unnecessary. Another anticipated problem was that the orcas would enter coves on the side rather than following the main stream. A boat with just its engine running was designated to guard the coves. In one case, the whales went under a boat into a cove. A boat with a banging pipe was able to return the whales to the main stream. No other problems, either anticipated or unanticipated were encountered. Following completion of a final planning meeting, placement of the boats began at 12:30 P.M. on Thursday, October 6. Once all boats were positioned, the orcas were located about 2.5 km from open water. A boat not banging pipes was used to move the whales farther from the entrance to Sweetwater Lake. At this point, the orcas were milling in a tight "ball" in contrast to the wide spacing observed prior to the entrance of the boats into the lake. Once we felt the whales were a safe distance from Sweetwater Lake, people began banging pipes. The whales showed no additional reaction to this initially. After a few minutes, they began moving slowly towards Indian Creek, the intended exit. Two peninsulas form the boundary between Barnes Lake and Indian Creek. The orcas stopped for quite a while before entering Indian Creek. Thus these peninsulas appeared to form the first psychological barrier to leaving the lake. Once in Indian Creek, the whales proceeded until the first island. This island caused a significant narrowing in the channel. The section between the peninsulas and the island had been designated a "holding area". I checked on the condition of the rapids and concluded that it would be better to wait for the current to slacken. The whales milled against the island for a while, and then moved a short distance back towards the boats, which held positions between the peninsulas. Thus the island appeared to form a second psychological barrier. After the current slackened, the drive continued. The orcas moved past the island, and proceeded to a kelp bed. They milled in front of the kelp bed, then moved out of the mainstream into a cove. A boat with banging pipes was able to move the whales out of the cove and back to the edge of the kelp bed. The drive line reached its closest point to the whales, but the orcas continued to mill next to the kelp. The drive was paused, because prior observation indicated that increased outbound current would cause the kelp to lie down, giving the whales better access to the channel. After a few more minutes, the orcas went through the kelp bed. Thus the kelp bed appeared to be the third and most significant psychological barrier. The whales proceeded to the island which formed the narrowest portion of Indian Creek. The orcas had passed over the "rapids" (which were simply a shallow ledge at that time due to the slackness of the current) without any difficulty. The whales milled briefly at the island, and chose the narrow channel rather than the wider dead end bay. The "rapids" would have constituted a physical barrier at other tidal states, but did not appear to be even a psychological barrier at high slack. The combination of the rapids and the island would have constituted a fourth barrier if the orcas had tried to leave the lake on their own at any other tidal state. The drive was completed about 3:15 P.M. The whales were followed for an additional hour to ascertain whether they were headed for open water, or into dead-end coves or bays. After exiting the creek, the orcas headed towards a flock of birds which appeared to be feeding near shore. After traveling under the birds, they headed for mid-channel. They continued out to Whale Passage. They then headed towards Clarence Strait, rather than towards Whale Pass, which is at the end of an inlet. After leaving the flock of birds, the whales exhibited normal grouping patterns of seven abreast or subgroups of 3 and 4 individuals, normal surfacing postures, and normal respiratory intervals. They paused about 3 km outside the lake. It is unclear whether they paused to try to determine their location, or they were just resting. After this pause, they continued toward open water. OPTIONS REJECTED A number of possible interventions were considered and rejected. First, handling the orcas for medical exams prior to attempting to coax them from the lake was considered. However, observation of the surviving whales the day before the drive indicated that they were likely to be in good enough condition to take care of themselves. Providing food supplements to the whales until they figured out for themselves how to get out of the lake was considered. However, the skittish behavior of the orcas around boats suggested they would be difficult to feed directly unless their condition worsened and they stranded on a beach. Supplementing the lake population of fish was considered impractical due to the large quantity of fish needed to feed that particular group of whales. The use of nets rather than noise to herd the orcas was rejected due to difficulties anticipated from bottom topography, complications due to kelp beds, and the risk of entanglement. The use of explosives such as seal bombs was deemed unlikely to be necessary. The use of a single sound source was rejected due to the difficulty in directing movement in a particular direction, and the consequent risk of stranding. The play-back of killer whale calls was rejected because the population affiliation of the whales was unknown, and hence their response to a play-back would be totally unpredictable. TIMING OF THE INTERVENTION On October 3, the first day of close observation, it was determined that some form of intervention was likely to be appropriate, and preparation for the drive option began immediately. Personnel and equipment began moving to the area on October 4 (due to the remoteness of the area, it was not possible for all of the key people to reach the area in one day). Intervention was not attempted on October 5 because local resources were committed to an earthquake preparedness drill, and more information about the lake itself and the conditions of the whales were needed to plan for a safe intervention. Intervention took place on October 6, the day with the best tidal conditions and suitable weather. October 7 would not have been possible because bad weather would have precluded the use of the small boats. Tidal conditions progressively worsened after October 7. DISCUSSION The decision to intervene was based primarily on the situation (population density and food availability considerations) and subtle abnormalities in behavior and appearance. Thus it is possible that the decision to intervene was premature. However, the four points during the drive where the orcas stopped supported my impression that it would be unlikely for the whales to leave the lake on their own. The death of the second whale, which was not confirmed until after the drive, supported the impression that the whales would remain in the lake until death rather than leave when their condition became poor. The marked change in behavior upon leaving the lake suggested their welfare had been improved, whether or not intervention was necessary to save their lives. The lack of significant adverse reactions to the drive (changes in individual spacing, direction of movement, and an occasional fluke slap were all that was observed, and these are not uncommon responses to recreational whale watching) indicated that the intervention was humane and probably caused the least possible disturbance. Presumably, early intervention as selected here was more beneficial to the orcas than delayed intervention would have been. In the latter case the whales would have been in worse condition and less able to take care of themselves when they did leave the lake. ACKNOWLEDGMENTS I would like to thank Russ Cameron and Peregrine Productions for organizing the logistics for this work, his assistance with data collection, and financial support. Louisiana Pacific, Ketchikan Air, The Marine World Foundation and Sea World provided financial support. I would like to give special thanks to Nani Fannemel and Geno Namaau of Whales Resort for providing logistical support to the field team. Gene Hering, Victor Ives, and Mike McKenzie also provided assistance in the field. I would like to thank many people from NMFS (both in Seattle and Juneau) and the U.S. Forest Service for helpful information and advice. I would like to give special thanks to Laurie Gage of Marine World for her advice and assistance with coordinating the intervention. I also give special thanks to Mike Demetrios of Marine World / Africa USA for encouraging me and Dr. Gage to participate, his behind the scenes work on logistics, and his usual advice to "do what's best for the whales." Mike Farley played a key role in organizing local responses from Whale Pass and Coffman Cove. I thank him and the people of those communities for their excellent work. The California Marine Mammal Center provided the poles used in the drive and staff support. Finally, I would like to thank NMFS for responding promptly to all requests for permission to take actions to benefit the welfare of the killer whales in Barnes Lake.