#ffis, lurillrr{{flfl!fl!illll CCIIS:RVAIlC;l I t.l , iPAIL$I[iiT0t A$ LT::OI"IA::AO:MEIIT ?_* *.-. r;; t .{.,.. t w.A.::i.l 'i';,1r, New ZealandFur Seals and Oil: c0M0. t An Overview of Assessment, Treatment, Toxic Effects and I Survivors h ip t The 1991 Sanko HarvestOit Spitl I I t t I I I Report to tlre West Austialian I Departmentof Conservationand T Land Management I Nicholas J. Gales + 4t oi*.a* f'')?W_ tett,) Marine Mammal Consultant I 50 Beamish Avenue Mount pleasant "tt.-- I Western Australia 6153 reJJ \L*' .--te*{- fldt*,l " 'it I August l99l . i4a,.1 L\tl'"* .l^. ,*.'l I THELIBRARY i}ji73$ DEPARTMENTOF CONSERVATION & LANDMANAGEMENT l| .td WESIEBNAUSTHALIA 2 t Table of Contents I ABSTRACT t 2 INTRODUCTION 2.1 An historical perspective:pinnipeds and oil t 2.2 A summary of events 2.3 The life history of New Zealand fur seals 3 METHODS t 3. I Assessmentof scale of impact 3.2 Objectives and methodology of the fur seal rescue program l: 3.2.1 .Assessment of degree of oiling 3.2.2 Blood collection procedure I| 3.2.3 Tagging 3.2.4 Selecrion of cleaning chemicals I| 3.3 Environment and operational logistics 4 RESULTS I: 4.1 Scale of impact 4.1.1 Hood Island 4.1.2 Seal Rocks t 4.2 Animal handling and cleaning operation 4.3 Clinical evatuation and initial treatment t 4.3.1 Hood lsland 4.3.2 Seat Rocks I 4.4 Haematology 4.5 Survivorship and mortality 4.5.1 Hood Island I 4.5.2 Seal Rocks 4.5.3 Mass as an index of bodv condition I 5 DISCUSSION 6 ACKNOWLEDGEMENTS t 7 LITERATIJRE CITDD t 8 TABLES AND FIGURES t I t t

I {r' I ABSTRACT

'sanko I on February l4th l99l the burk ore carrier Harvest" was wrecked and spilled 700 tonnes of heavy firel oil into the sea along the south coast of western

t Australia. A portion of this oil was washed onto near-shoreislands, two of t which supponed breeding popurations of New Zealand fur seals Arctocephalus forsteri.

I At the tfune of the oil spill the l99l cohort of pups were aged between two weeks and two months and were the onry age class of seal contaminated.Thirty

t niae pups on Hood Island and up to 172 pups on seal Rocrs were contaminatedto I varyiug degrees with oit. All affected pups were captured atrd restained in pens. A non-solvent, biodegradable, non-ionic detergent and a hydrocarbon I solvent were used to remove the oil from the fur seals' pelage. The rocks in the area of the fiu seal corony were creared of oit before the pups were released.

I Analysis of lpematology and blood chemistry demonstrated a general stress

leucogram at the time of the o spill which returned to aormal values within t two motrths. Minor aberrations in biochemistry reflected stress and results of I handling rather than significant hydrocarbon toxicity. Mortality of pups on Hood Island was between riro and 33%. on seal Rocks Eortality I was at leest 6.4%. Man mass of oil-fouled pups was not sigtrificantly diff€rent t to pups from an unaffected colouy near-by ar the time of the oil spill, but decroased significantry over a two week period before returning to normal I ranges after two montbs. Prompt and efficient removal of the oil from the fur seals appears to have minimised t the potential impact on the fur seals. This species response ro such a toxic challenge is in contrast to the high mortility reported in sea otters I following the Exxon Valdez oil spill. I I I' I (-) 4 I INTRODUCTION

I The grounding and subsequent sinking of the Japanese owned bulk lSanko carrier Harvestn on 14 February l99l 6nm south of Cape Lc Grand, r western Australia initiated a sequence of events unique to Australia's maritime I and environmental history. The primary pollutants released into the marine ecosystemas a result of the wreck were approximately 30,000 tonnes of the I highly soluble fertilizers, as well as 700 tonnes of bunker oil. The scope of this report is restricled to comment on the impact of the oil on two New Zealand fur

I seal ArctoceDhalus forsteri colooies in the region. Other reports have been t commissioned by representatives of the west Ausralian state government thst cover the many aspects of an environmental disaster of this magnitude. I I was commissioned as a marine mammal consultant and veterinarian by the West Australian Department of Conservation and Land Management to

I assess' treat and monitor marine mamnals affected by the sinking of the sanko I Harvest. I 2.L An historical persgective:oinnioeds and oil

I The amphibious life history of seals presents special considerations t when dealing with the potential risks of oil contaninoliqn in this group of marine mammals. The exteDsive nature of hydrocarbon exploration and I transport has resulted in few marinc ecosystems being safe from potential contami<ion with oil. The past four decadeshave seen at least 29 episodes of I encounters between pinnipeds and oil (St. Aubin 1990), though these have I resulted in few quantitative accounts to allow'us to acaurately predict the impact of oil or to formulate meaningfut treatmenl and action plans. Most I reports have described oil fouling of grey and harp seals. large scale mortality has never been I observed, but oil has clearly been implicated in some deaths. I l a'.1 t Fur seals possessa tlenre u'der-fur used t, r,rapa layer trf air close to 0re skin which assists in thermoregulation.Fouling of this pelage wio oit leads to I thermoregulatory and energetic imbalance, the insulative value to the pelt being reduced by as much as 50% (Kooyman et al 1926). Few reports exist that

I describe large scale oiling in wild fur sears, thus providing littre predictive data. I The Exxon valdez oil spill in 1989 resulted in the contamination of over three hundred sea otters. Like fur sears these marine mammals have a dense un

T the treatment and rehabilitation of these animals was used as a predictor for t imFact on the fur seals described in this reoort. t a) A summarv of the events

"Sanko I On Febnrary 14 l99l the Harvest", a Japaneseowned, 30,000 tonne I deadweight bulk carrier bound ftom Tampa, USA to Esperance, Western Ausralia struck an unnamed 6nm south of cape Le Grand (35 kn south-east t of Esperance). within 24 hours the ship was rendered unsalvageableand broke up and sank over rhe forrowing two week period. The 30,000 tonnes of soruble I fertiliser (22,000 tonnes of dlammonium phosphate and g,fi)0 tonnes of triple superphosphate)was rapidly dissolved and dispersed. A monitoring programme

I commissioned by the West Australian Environmental protection Agency I detected no adverse effects from the fertiliser. The 700 tonnes of heavy fuel oil was not able to be removed from the ship or contained in the adjacent sea. The I majority of this oil washed up on beachesof the cape Le Grand National park, with some oil impacting near-shoreislands in the vicinity.

I Two days after the ship,s grounding oil was seen on the northern end o{ I Hood Island (34"09's, 122"03'E) and the fo owing day officers from rhe west Australian Department of Conservation and Land Management (CALM) I flew to T I 6 I the island hy helicopter to assessthe damage. A smafl colony of New Zealand fur seals was found to be impacted and a rescue operation was mounted the I following day. Petsonnel remained on Hood lsland from l?th February until 24th February, the seals having being cleaned and released on 2lst February. t On the l9th February aerial survey work reported oil on Seal Rocks (34o01's,121"40'E), I the site of anorher colony of A. forsteri. A rescue operation was mounted at this site on 2lst February until 24th February, with workers I being taken to the island on each day, but not remaining overnight. During fruther aerial survey work a new colony of fur seals was found r on Libke Islaad (34o13's, 122o04E').This island was not affected by oir and was t visited on 24th February to obtain mass data from fur sears unaffected bv oir for comparison with affested fur seals, t Oil was observed on roc\r platforms on several other near-shore istands. the worst affected being Figure of Eight Island (34.02'5, 121"37,8). Two

I Ausralian sea lions Neophoca cinerea were observed on this isrand with oil on t tbeir mats. No other seals were observed to be affected by the oil spill on any other islands. I Following the fur seal clean-up operation visits were conducted to Hood Island (on 6th March, r3th Match, 20th April "no itn July) and Sear Rocks (on

I 8th March, l3th March, 2l April and 7th July) to assess survivorship of affected I animals. Libke Island was arso revisited for further comparative mass change data on 8th March, 20th April and 6th July. I 2.3 I I The New Zealand fur seal Arctocephatris forsteri breeds in the New Zealand region and on the southern coasts of western Australia and South (Shaughnessy I Australia 1990). An estimate of approximately 4,6fi) A. forsreri are found along I the south coast of Western Australia (Shaughnessyand Gales 1990), I t rI;i

almost all of which I are in the Recherche Archipelago. A, forsteri breed annually in December and January, the bulls holding territories during this period, Following the I birth of the pup the mothers remain ashore for abour ten days during which time they are mated by a territoriar male, The cows then I begin making foraging trips to sea which last three to five days, returning to spend two I to four days with the pup. As the pup gets older the cow,s feeding trips become longer, and the temporarily abandoned pups gather .in groups and ofrcn play in protected I rock pools. The pups are suckled for almost a year and will remain in t the general vicinity of rheir natal site during this period. t METHODS I 3.1

Until recently I knowledge of marine mammal poputations in the Recherche fuchipelago I was scant. Fortunately, since l9E7 thorough surveys of the only two native pinniped species, the Austrarian sea lion and the New Zealand fur seal, I have been conducted in this region (Gales 1990, Shaughnessy and Gales 1990), providing recent data on the disEibution of these species' These data I were used to identify key terrestrial locations to assessfor impact. Bottlenose dolphins (Tursioos rruncatus) and Common dolphins I (Delohinus delphis) are abundanr in the region with sightings of other I Cetacean species being uncommon during February. Helicopters were used to monitor the movement of the oil slick and, where necessary, I to land on isrands for more deh'ed assessment.Mosr isrands 40nm east and west I of the wreck site were surveyed. If cetaceans were seen thev were observed from the air for aberrant behaviour, I I I 'l I 1i0 E I Where impact on pinnipeds was determined the approximate number, age class, behaviour and degree of fouling of the animals was noted. The level of I contamination in the immediate environment was also assessed. I T 3,2 Objectives and methodolo&r of the fur seal rescue program I At the major sites where oil conramitrationof firr seals was recorded the I objectives wete: - sccuratety record lhe number and age 8nd sex class of affected seals - t cspture and temporarily contain contaminated seals - t remove all oil from the local environment before release of treated seals - remove oil from contambated seals - t clinically examine, quantfy degree of oiling, weigh, measure length, treat if indicated, collect blood and tag all affected seals prior to release - r minimise time of clean up operation in order to minimise potential impact I of disturbance - collect all carcases for post-mortem examination - t revisit the site at regular intervals to assess impact of the oiling event and survivorship of coltaminated animals (criteria for frequency of visis to I be determined by dau from preceding ass€ssment)

I 3.2.1 Assessmentof degree of oiling I The degree of contamination of individual seals was quantified using an

I arbitrary scale of 0-5. Nil contamination being assigned 0; animals that had oil I completely covering their coat being assigned.5. I I I I /,\'.\ 9 I 3.2.2 Blood collection procedure

I Blood samples were collected via venipuncture of rhe lateral gluteal vein- Twenty gauge needles were used and blood was collected ioro three t vacutainef tubes with either no anti-coagulant, 15% EDTA (K3) or potassium t Oxalate. Blood was sent to Vetpath laboratory Services for analysis. I I r 3.2.3 Tagging T All handled ftr seals were tagged in the caudal axillar of both fore flippers with cattle ear Ags (Sidney ear tags, StockbrandsCo. pty Ltd, Western t Australia). The tags were not oumbered so a permatrenr ink marker pen was used to number the tags initialry, however when the numbers were found Dot to t last the remaining tags had numbers burned into the surface using a heat I engra v er. T 3.2.4 Setection of cleaning chemicals

I Two cleaning agents were used to wash oil from the coats of oil-fouled

fur seals. selection of appropriate chemicals was constrained by logistics and in I particular supply and availability. As such, chemicals available locally in t Esperance in sufficient quantity for such an operation were utilised. "Dawn Dr Randall Davis had advised that detergent" (made by proctor and I Gambol) had been successfulryused to crean oil from the fur of sea otters . after the Exxon Valdez oil spill. Unfortunately this was not available in t Australia. "CT I 18 concentrated cleansing gel. (distributed and made by Chemtech Ptoducts) was selected and trialed. It is a neutral pH, I non-ionic detergent with a I T ( tr l0 phosphatebuilding system that worhs well in har

I 3.3 Environment and ogerstional logistics I The islands of the Recherche Archipelago are typically high granitc I monoliths with low , sparse vegetation cover of scattered shrubs, grasses and I herbfields. Beaches are rare. I:nding on such islands from the sea is F treacherous and usually constrains the supply of bulky equipment. As a result helicopters were used to ferry personnel and equipment to work sites. t-anding I sites and aerial approaches to islands were serected, when possible, to minimise T impact on seal colonies. Radio communication with a centrar base in Esperance was maintained T via VIIF and HF radios.

I RESULTS TI T 4.1 Scale of imgact Oil was seen on several near-shoreislands, Hood Island and Seal Rocks T being the sites of impact otr A. forsteri. The two sea lions that were observed I with oil on their coats on Figure of Eight Island were not observed again and I I

I T h ll thus were not captured, treated or assessed.No other sites werc found where oil T fouling of seals had occurred. T T 4.1.1 Hood Island Most of the oil !o wash onto Hood Island was found in a 300m area on Oe t north-westem side of the istand. This is in the immediate vicinity of a sma I colony of A. forsteri. The oil accumulsted in low wave energy areas and thus fouled the waters snd rocks in thc areas where most of the pups congregate. The areas of higher I wave energy were mostly oil free.

At the time of the o spill pupping had fitrished and the territorial males T had left the site. The pups ranged in age from approximately two weeks to two months old. A survey conducted three days before the oil spill had counted 73 f T forsteri made up of one sub-adult male, 12 cows, 4 juveniles, 29 pups and 22 t unknown agey'sexclass (Shaugbnessy and Cheal l99l).

The initial suwey of animals conducted by officers from CALM on lTth I February found that arl observed pups had been heav y fouled with o . Adutts were t difficult to observe at close qusrters as they move into the sea when approached, but no adults were observed with evidence of oil on their coats. The cows juveniles I and tend !o enter and leave the water in the areas of high wave activity aad as these sites werc not affected by oil it seems rikely that impact on I these age groups had been minimal. Temporary T holding pens were constructed on the island using chicken wire with tarpaulins for shade. A toral of 39 pups were captured and placed in the pens, all I of which were heavily oiled. As the pups do not vedture to sea at this age it was assumed that the entire cohort had beeo cilptued. I A large amount of oil remained on the rocks and in the relatively protected I waters of the rock pools at the time to citpture of the pups. I t t , )r" t2 T 4.1.2 Seal Rocks t The size of the A. forsteri population on Seal Rocks is larger than that of Hood Island but the degree of impact from the oil was less. No survey had been F conducted at this colony during rhe 1990/91 breeding season to provide data on pre-oil spill population size. A survey conducted in January 1990 had counted a F total of 307 fur seals, of which 187 were pups (Shaughnessylg0). This aurhor estimated the total Seal Rocks population to be 752. F The inspection of this colony on 2lst February reveal€d varying degrees F of impact around the island. On the eastem end of the colony a low valley of rock opens to sea. The pups in this area (sector l) had been significantly oiled F and some oil was still present oo the rocks. On the mid northern end of the island (sector 2) there was no evidence of oil on the rocks, but some pups were t found to be fouled with oil with others unaffected. A large group of firr seals on F the Western end of the island (sector 3) was found to be unaffected by the oil and there was no evidence of oil on the rocks. There were no adult animals F observed that showed evidence of oil-fouling. From the general lack of oil that was found around the island it appeared F that an oil slick had been in the immediate vicinity of the island, with some washing ashore at sector l, but most of the oil had moved awav from the island F at the time of initial assessmenr. F Pens of the type co[structed at Hood Island were set up at the three sectors (1,2 & 3) on Seal Rocks, Forty three pups were captured and penned at F sector l, E0 pups ar seclor 2 and 49 at sector 3 (a anal of 172 pups). As many pups F as possible were captured, whether they were sffected by oil or not. Some pups in sector 3 were unable to be captured due to the difficult rocky terrain and t rough seas. It is unlikely that tbese pups were fouled with oil as impact in this F sector did not appear to have occurred. F t t 't.,1 l3 t 4.2 Animal handling and cleaning ooeration t The capture of the fur seal pups was relatively Etraight fofward as, at this age' they tend to remain hidden under rocks. They will not attempt to swim t to sea. The pups were grabbed by one or both of the rear flippcrs and as they only weighed between six and l5kg were readily carried to the holding pens. T Thorough searches through the colony were necessary to capture all pups. I Trials were conducted on the most efficient method of cleaning the oil- { fouled pups. A plastic bin of lm x 0.5m x 0.5m was used. The pups were I physically restrained in the bin aod wet down with sea water. concentrated "cr 18" was poured over the ftrr and massaged into the pelage. A stiff bristled hair r brush was also used to augment the distribution of the detergent into the ftrf.

The pup was then thoroughly rinsed and the procedure repeated. At this stage a T significant amount of the detergent remained in the firr. "preen' was then I sprayed over the animal's coat and massagedand brushed through &e fur. A thorough rinse completed the washiirg procedure. The "preen. left littte

I detergentresidue in the pelage and at least 90% of the oil was estimated to have t been removed. care was taken to avoid chemical conact with the seal's eyes or mouth. Initially water for rinsing was carried in buckets and poured over ihe I animals. Later a petrol powered water pump was used that increased the efficiency of the rinse and shortened the length of the washing procedure. The il entire process took between 20 and 40 minutes, depending on the degree of I fouling. A team of three people was ideal for washing one pup. It was possible to repeat the procedure to further improve the effectiveness of the wash, T however, in order to minirnise the amount of time spent at the colony, and hence the degree of disturbance caused, this. was not gonsidered advantageous.

I After cleaning it appeared that the natural oils had also been stripped h from the coat. These natural oils had been naturalry replaced in the coats by day 60 after cleaning. I I T ,4 t4 The pups tolerated the cleaning proccdure reasonablywell, an

I 4.3 t t 4.3.1 Hood tsland All 39 pups on Hood Island were heavily oiled and w."e crassedas 4-5 for I degree of oiling. Prior to the commetrcementof the cleaning operation no mortalities were I recorded. O4e pup (tag no. y0l) died in the holding pen prior to release,

During I the initial clean-up operation the degree of toxicity the pups may be expected to suffer was untnown. Resirlts from the analysis of blood were I not available until after the fur sears had been creaned and rereased. Advise from scientists h involved in the crean up of sea otters in Araska indicated that dehydration, T low blood glucose (from shock), pulmonary emphysema and I h $l 15

corneal ulceration were the primary medical problems exhihited in the first

three weeks following oiling (Dr. T. Wiltiams, personal communication). As a

prophylactic measure it was decided to .dminister lactated ringers via

sub-cutaneousinjection and dextrose solurbn (5%) via stomach tube. Eight fur

seals were administered both lactated ringsrs and dextrose, 16 were treated with

lacated ringers only and 14 were not trdrcd (doses are given in table l). The 14

untreated seals were the last to be wash€dand treatment was withheld as time

did not permit us to do so without holdi4 the animals in the pcns for a further

nighL It was considered more important b release the animals and leave the

colony at this stage. Chloramphenicol B. P. eye ointment was administered to all

treated seals.

Clinical signs of toxicity were nd evident in the seals examined during

the cleaning operation. Small amounts of a mucus discharge were observed in

several seal pups, however most eyes wcrc clear and were scored at 4-5 (an

arbitrary scale of 0-5 was used). No corupal ulceration was observed.

The extensive oil-fouling in this gmup of frrr seals was likely

responsible for some degree of thermorgulatory disturbance. However the

relatively temperate conditions that preveiled during the operatiotr (the oil

spill occurred during rhe austral summcr) minimisid thermal challenge to the

animals, During the period the fur seals were penned several were seen

shivering. This may have reflected th€rdoregulatory disturbance or may have

been associatedwith stress.

Generally, Oe clinicat state of thc fur seal pups from the time of capture

until release was good, atthough the animor that died (tag no. y0l) and one

other (tag nos. Y2l) were moribund and weak. t e:i l6 T 4.3.2 Seal Rocks il The degree of oil-fouling of the fur seal pups on seal rocks was less rhan those from Hood Island. Prior to capture and washing 149 pups were assessed T visually for degree of oiling using the arbiuary l-5 scale; 15% (n=22) wete i entirely free of oil, 8% (n=11) were categorisedas L, 37% (n=56) as 2, 2j% (n45) Il as 3, 8% (n=ll) as 4 and 9Vo (n=14) as 5. Eighty four percent of rhe animals I classed as 4 or 5 were found in sector l, the remainder in secor 2. Lactated ringers solutioo and dextrose solution were not administered to F the fur seals on Seal Rocks. Preliminary results from analysis of the blood collected from Hood Island fur seals had indicated that such Eeatment may not F have been necessary (see section 4.4). Furthermore, the impact from oil on Seal Rocks had been less. All seals were treated with chloramphenicol B. p. eye F ointment. F The washing procedure employed at Seal .Rocks was the s:tme as that used on Hood Island, but because of the large number of animals involved six F separate washing tqrms were set up to speed up the process. Clinical examination of all animals prior to release indicated no obvious F evidence of toxicity. There was no observable clinical differeDce between the F worst affected animrls in. sector I and those unaffected bv oil in sector 3. F 4.4 Haematologl F Fourteen blood samples were collected from A. forsteri pups on Hood Island and thirty six samples from pups in the three sectors on Seal Rocks prior I to their release (table 3). A further 13 blood .samples were collected from tagged pups on Hood Island on 20th April 1991, and 21 from tagged pups in sbctors I and I 2 from Seal Rocks on 2lst April 1991 (table 4). Sk pups (two from Hood Island I and four ftom Scal Rocks) were bled on boih occasions, comparisons between I I Q-1 17

I the consecutive blood r samples collected from thesc pups and between the mean pooled results of alt btood samples are presentedin table 5. There are no published normal values for haemarology and biochemistry of A. forsleri i for comparative purposes. As such, ihe analysis of the blood results reported T here is based principally on comparisonsbetween sampres couected in February and April. The samples co[ected in sector 3 in February may be crose to I normar values as rhey are likery to be reratively free of toxic effects r of the oil, but may r€flect stress from the clean-up operation (animals were penned overnight prior to blood sampling). Unfortunately no sector 3 animals were bled in April, the samples collected ftom the moderatery affected sector 2 animals at this time may represent close to normal values. Haemoglobin (Hb) and packed cell volumes (pCV) were highest for animals aom Hood Island, with , decreasingrevels from fur sears at sector l, 2 and 3 consecutively. It is unclear if rhis represents true haemoconcentrationin the Hood Island animals as there was no statistically significant difference (t test) for Hb or PCV between the samples collected in February and April for any of the groups of animals. The degree of variation in the Hb and pCV was small. A highly signifrcant decrease(t lesr; p < 0.0005) in white btood cells (wBC) occurred between February and April, This decrease was primar y accounted for by a decrease in the percentage and absolute numbers of neutrophils present. concomitant to this tbere was a highly significant increase (t test; p < 0.0005) in tymphocytesfor a[ groups of animals. There was a significant incfesse (t test; < o.ol p < 0.025) in the number of eosinophils for the Hood Island animals, but not for those on Seal Rocks. Assuming the samples collected in April are closer or equal to normal values than the February samples,then at the point of release the fur.seals demonstrateda leucocytosis, neutrophilia, monocytosis, tymphopenia and eosinopenia.These findings are typical of changes induced by acute stress. T {1 l8 T Total plasma protein and total serum protein levels were significantly higher in April than February ( rasr; p < 0.0005) for all groups of fur seals; an t increase in the circulating serum gtobulins being the protein fraction responsible for the increase.

T Aspartate aminotransferase (AST), Gamma glutamyltransferase (GGT) T and urea did not vary significantly in any of the oiled fur seals in this study. Alanine aminotransferase(ALT) decreasedsignificantly (t test; 0.005 < p < 0.01) I for the overall pooled blood samples from February to April. This decreasewas significant for the fur seals from Seal Rocks, but not for those from Hood Island. I The degree of changes were on a relatively small scale. Alkaline phosphatase (alk phos) levels decreased significaatly for all T groups of (t seals test; p < 0.0005). These changes were significant for seals from t Hood Island and Seal Rocks. Creatinine phosphokinase (CK) levels were highly variable and l appeared to iDcrease for all sub-groups of seals between February and April. Hood island was the only site were the increasewas significant (t test; 0.01 < p < I 0.025). Creatinine (creat) decreased significantly between February and April on Hood lslaod (t test; p < 0.0005) and increased significantly over that period on I seal Rocks (t tesq 0.01 < p < 0.025). The magnitudeof the changesat both sites was small.

I Similarly, glucose (gluc) underwent a significant 40% reduction in

values on Hood Island (t test; p < 0.0005) and a significant 44% incteaseon Seal I Rocks (t test; p < 0.0005) over the period from February to April. I A highly significant increase in blood cholesterol levels occurred with all sub-groupsof seals (t test; p < 0.0005) concomitant to sigtrificanr decreasesin I serum sodium (Na) and potassium(K) ( test; p.< 0.0005). I A decreaseof up to 42% in circulating bilirubin (bil) was highly I significaot at all sites (t test; p < 0.0005). I t.t 19 I Plasma cortisiol levels were highly variable and generally decreased over time. A. forsteri pups on Hood Island were the only group of animals to

demonstratea ststistically significant decreasein cortisol (t test; 0.01 < p < : 0.0025). Plasma iron (Fe) levels, which are also used as a general indicator of

: stress, tended to increase in most sub-groups over time, Hood Island animals

once again being the only group to show a significant increase (t test; 0.01 < p < I 0.002s).

Analysis of levels of serum hydrocarbonsvia a specialisedassay have not b€en completedand will be reportedin due course.

4.5 Survivorshio and mortalitJ

4.5.1 Hood Island

Morklity of pups on Hood Island is known to be at least lSTo as five of the

39 agge.d pups (nos. H0l, H02, H10, HIZ and H28) were found dead during the

period from the oil spill until rhe final visit in July 1991. This estimate of

moftality is almost certainly an underestimate as pup carcases were found

among the rocks below the high water storm level and thus other carcases may

well have been washed into the sea and not retrieved. The mortality level on

20th April is known !o be less thaa 33% as 26 of the original 39 live pups were

counted around the island. At this stage tho pups were highly mobile and were

competelt swimmers, it is therefore likely that we underestimated live pup

numbers and thus 33% mortality would be an overestimate.

It is not possible to differentiate which of the mortalities occurred as a

direct result of fouling with oil or from the disturbance caused by the clean-up

operation from those which occurred from unrelated causes. Only one of the

csrca$esretrieved from Hood Island had been used for blood sampling (HlO);

thiE animal showed unremarkable haematology and biochemistry. G 20 Unfortunately only one carcase was in a sufficiently fresh state for post-

mortem examination. There were no remarkable findings during this examination,

H02 and Hl7 were both weighed on two occasions since their release

prior to their death. Both pups had signlficant weight loss (table l). This may

have been due to toxic effects of the oil and/or from a failure to feed to from their mothers.

4.5.2 Seal Rocks

Meaningful counts of pups on Seal Rocks were not attempted during the

visits conducted after the clean-up operation as the animals were too mobile for meaningful data collection.

Six untagged pups died as a result of asphyxiation and crushing in a

capture pen. A large group of animals had been left unattended overnight in this pbn (in secor 3).

A further five pup carcases were found during the visits to Seal Rocks,

one of these animals (S43) had exhibited a 3r% mass loss over an lg day period

post release. Two other pups (S28, Sl2?) had exhibited mass gain, the remaining

two pups (546, Sl05) were not recaptured live after the release (rable 2).

These mortalities account for a minimum of a 6.4% mortality. The carcase

of Sl27 was found on a mainland Australiau beach adjacent to seal Rocks. It is

likely that this animal died on Seal Rocks and was washed into the sea. This

removal of pup carcases from the island leads to an underestimateof mortality.

546 had been blood sampled at release. Two percent of rhe leucocytes

were banded neutrophils, but the remaining blood parameters were unremarkable. T L'i" 2l None of the carcases found on Seal Rocks were sufficiently fresh to |' facilitate meaningful post-mo(tem examination.

|' I 4.5.3 Mass as an index of bodv condition At the time of release there was no significant difference between the mean mass of I the seal pups on Hood Island, Seal Rocks and the unaffected A forsteri pups on Libke Island, The pups from sector I on Seal Rocks were I significantly lighter than those from Libke Island (t rest; p < 0.0005). I Thirteen days after release the Hood Island pups decreased in mass whilst pups the in the three sectors from Seal Rocks increased in mass (figrre l, table 6). At this point |' all sub-groups of seal pups were significantly lighter than the unaffected pups on Libke Island (t test; p < 0.0005). I The mean mass of all oil-fouled groups of fur seals decreased significantly between 13 and 18 days after release,

I Assessmentof mean pup nuss 56 and 133 days after release resulted in no significant I difference in mean mass between pups affected by the oil and those I not affected (figure l). I DISCUSSION

The present F study provides some of the first quantitative data assessing impact of oil on fur seals. In the context of dealing with an environmental disaster ft such as this one we were fortunate that the only age class of animals involved were F those that were readily captured, contained and handled and that follow-up during the pre-weaning period was. possible. This allowed maximum potential for ft an experimental assessmentof the degree of impact. In many other cases access F to impacted animals is difficult and handling procedures are I I ir'i, 22

complicatedby the necessitateduse of chemical restraint and the need to

remove the animals, albeit temporarily, from their natural environment.

Fur bearing marine mammals (ie fur seals and sea otters) a.re most

vulngrable to oil-fouling as the fur coat is an ideal matrix for retaining oil. A

high mortality was reported for oil contaminatedsea otters as a result of the

Exxon Valdez oil spill in 1989 (Willi8ms and Davls 1990). Geraci and Williams

(1990) noted set otters affected by oil experience problems via sysremic roxic

effects from ingestion of oil while grooming or from ingestion of contaminated

prey, intolerance to interruptions in feeding, energetic imbalance and from

behavioural problems associated with displacing them from their normal home

range. Many of these factors did not apply to the A. forsteri pups described in

this study as they were not displaced ftom their normal environment, their food

source was still maternally derived and presumably not contaminated and

grooming behaviour does not involve an oral component. Some level of

energetic perturbation was likely to have occurred as oil has been shown to

decreasethe insulative value of the pelt by as much as 50% (Kooyman et al

1976), but this would have been minimised by the temperate weather that

. accompaniedthe oil spill. st Aubin (1990) predicted that spilled oil would have

its greatest impact on young pinnipeds in cold, ice-6ound waters.

The clinical assessmentof contaminated fur seals during the clean up

operation gave little indication of significant, acute toxicology. Furthermore,

analysis of haematology and blood biochernistry reflected mainly a general

physiological stres$ rather than significant, systemic, toxic challenge. This was

mainly reflected in the stress leucogram. The reason for the relative

hyperproteinemia that developed between February and April is unknown. This

was not a response to dehydration (there was .no change in haemoglobin and

packed cell volume) and was specifically a hyperglobulinemia.

Immunoelectrophoresis was not conducted to determine the globulin fraction

that had increased. The changes were Dot great and may have been associated \/i 23

with an immune response to low-grade chronic inflammation. However,

haematology and blood chemistry are known to undergo major developmental

changes during an animal's early life. The small, but significant and consistent

changes in protein levels and several of the enzymes may be explained by the

two months that separated the blood collection procedures. This is almost

certainly truc of the decrease in levels of alkaline phosphatase(Alk phos).

changes in cholesterol may be explained by variations in the composition of

ingested milk over time. Many pinnipeds experience an increase in milk fat

content during lactation. The indicators of stress, cortisol and plasma iron, did

not vary significantly between February and April. This is likely a reflection of

acute stress being manifest in the capture and weighing operation itself.

Further analysis of blood will be done at a later date when results of systemic

hydrocarbon levels are known. These data will be the subject of a . scientific publication and will be submitted in due course.

The cleaning procedure and the chemicals used in this study were

effective for the removal of oil. There were no observed deleterious side-effects from the cleaning agents.

The overall impact on the fur seals on Hood Island and Seal Rocks does

not appear to have been great. An accurate assessmentof mortality was not

possible but was probably less on seal Rocks than Hood Island. Even so mortality

at these sites is unlikely to have had a significant enough impact on the affected

cohort to affect the overall viability of the colony. A thorough census will be

conductedat both sites in February 1992 to collect data on pup production as an

index of colony health. A. forsteri colonies along the south coast of Australia

appear to be increasing in size and number and this minor oerturbation shoul

A significant factor that led to minimising impact was the relatively

short delay between the oil spill and the commencementof an effective clean up

operstion. An operational commitment to rapidly supply personnel and 24

equipment to the affected sites was central to this. Furthermore, it appears that

the approach to minimise disturbance to the colony by treating the aninals

quickly and keeping subsequent visits to a minimum frequency and duration

was effective. Even though mush of the stress caused and probably a significant amount of the mortality was a direct result of our intervention it is quite probable that mortality would have been higher if this approach was not taken.

There was a high level of expectation from the public (elucidated through the media) for affected pups to be removed from the colony and treated and rehabiliated at a centre set up for this purpose. It is my belief that such a course of action would have resulted in a higher mortality rate of pups tbrough our inability to provide sufficient nutrition, the additional stress of such an exercise and the problems associated with displacement of animals from their natural environment.

ACKNOWLEDGMENTS

The successof this operation has been due to a great many people, only a few of whom are nominated here. officers from the GALM, particularly Bernie

Haberley, Peter Collins, Greg Pobar and peter bmbert, were involved in most aspects of the data collection, as were many dedicated volunteers from

Esperance, in particular . The helicopter crew from the west

Australian police air wing, particularly Clive Mayo, were extremely obliging in flying at difficult times and in marginar conditions to ensure that people and equipment had access to the islands.

Drs Terrie Williams and Randy Davis were tremendously supponive in supplying information, suggestionsand encouregementbased on their work on the Exxon valdez oil spill. Terrie williams also kindly organised the analysis of blood for hydrocarbon levels. 25

Dr Sue Beetsonfrom Vetpath suppliedrapid results ftom collectedblood assistedin data interpretation.

Alistair Cheal kindly drew the line drawing on the ftont of this report. wl 26

LITERATURECITED

GALES' N' J. 1990. Abundance of Ausrarian sea lions Neophoca cinerea arong the

southcrn Australian coast, and relatcd research. Report to rhe western

Australian Department of Conscrvation and land Management, South

Australian National Parks and wildlife Service and the south Australian Wildlife ConservationFund.

CBRACI, J. R. AND WILLIAMS, T. D. 1990. physiological and toxic effects on sea

otters. Iq Sea Mammals and oil: conftonting the Risks. Eds. Geraci. J. R. and st.

Aubin, D. J. Academic hess, New yorlc pp 2ll-220.

KooYMAN, G. L., CENrRy, R. L, AND MCALLTSTER,W. B. 1976. physiological impact

of oil on pinnipeds. Report to Northwest Fisheries Centre, National Marine Fisheries Sewice, USA.

sHAUGHNEssy,P. D. 1990. Distribution and abundanceof New Zealand fur seals

Arctocephalus forsteri in western Australia. Report to the western Australiatr

Department of Conservation and land Management.

p. SHAUcHNEssy, AND GALES, N. 1990. First survey of fur seals and sea lions in

westerD Australia and South Australia. Austrarian Ranget Bulletin s(4).. 46-49.

sHAUcHNEssY, P' D. AND cH&tL, A. J. 1991.survey of New Zearandfr' sealsin rhe

Recherche Archipelago, February 1991. Report to the Western Australian

Department of Conservation snd [:nd Management, {4 27

ST. AUBIN,D. J. 1990.fusiological and toxic effecrson pinnipe4s,|1 Sot Mammsls

and Oil: Confrontingrhe Rists. Eds. Geraci,J. R. and St. Aubin, p. J. Academic Press,New york. pp 103-123.

WILLIAMS, M., AND DAVIS, R. W. 1990. 1989 -T. Sea otter rehabilitationprognm: Exxon Valdez oil spill.Intcrmtional Wildlife Research, USA. I I I

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