Ciconia（福井県自然保護センター研究報告） 7: 13-24(1998)

Species and rehabilitation of seabirds oiled
in the accident of the Nakhodka, in Fukui＊

Yoshito OHSAKO １

INTRODUCTION
Oil pollution causes ecological damage, especially to wildlife. For example, a great numberof birds was oiled to death in the accident of the supertanker, Exxon Valdez in 1989 ( Piattet al. 1990 ) and during the Gulf War in 1990 (Symens & Al Salamah 1993, Evans et al.
1993). The effect of the oil spill and the change of the bird community, habitat use andbehaviours were analysed in many reports ( e.g. Jackson 1993, Day et al. 1995, Wiens et al.
1996). However, there have been few documents and analyses of the oil pollution damage
to seabirds and the rehabilitation of rescued birds except reports by Ohata ( 1988) and Ohataet al. (1993) in Japan.
The oil spill accident of the Nakhodka happened in the Japan Sea in 1997. The oil reachedalong the seacoasts of Fukui Prefecture. It is useful to document the status of oiled birds
and rehabilitation.
Oil spill and seabird rescue in Fukui
The Nakhodka, a Russian tanker, sank with 19,000kl of C-type heavy fuel oil in the Japan
Sea, off the shore of Shimane Pref. on 2 January, 1997. About 6,240kl of oil leaked in theaccident and floated toward the east. The bow section of the wrecked tanker, with about
2,800kl of oil, ran aground on the shore of Anto area ( 36 ﾟ 15'N，136 ﾟ 08'E) in Mikuni
Town, Sakai Municipality, Fukui Pref. on 7 January. The oil, including the oil leaking fromthe bow section, reached all the coasts of Fukui Pref. and was removed by people from 7
to about 27 in January.
The government of Fukui Prefecture organized the patrol, transportation, medical treatment
and rehabilitation of the oiled seabirds on 7 January in cooperation with the municipal office,Fukui Veterinary Medical Association and the Wild Bird Society of Japan.
The rescued birds were medically treated and cleaned in an animal hospital or the animal* Contribution from Fukui Nature Conservation Center, No.54
1.Fukui Nature Conservation Center. Minamirokuroshi 169-11-2, Ono-shi, Fukui
912-0131-1-

hygiene center in Fukui City, which was about 17 km from the nearest seacoast. Aftercleaning, they were rehabilitated at Fukui Nature Conservation Center in Ono City, which
was another 31km from the hospitals.
The recovered birds were transported by airplane to Hokkaido and were released on the
shore of Yufutsu Coast, where the oil had not yet spread. The oil stocked in the bow
section was extracted out until 25 February. The stranded bow of the tanker was lifted
onto the ground on 20 April.
METHODS
The municipal staff, the members of the Fukui branch of the Wild Bird Society of Japanand volunteers patrolled the seashores in Fukui from 8 June to 10 March. The species andnumber of rescued (live) or collected (dead) seabirds were recorded every day in eachmunicipality.
The rescued birds were cleaned and medically treated in animal hospitals and rehabilitatedin Fukui Nature Conservation Center. The birds were kept separately in a box ( 60cm(l)×60cm(w)× 90cm(h)) with a net bottom. Hand made pools (ca.200cm(l)× 200cm(w)× 40
cm(d)) were prepared for swimming and the bathing of the birds. The pools were filled withfresh water. During the rehabilitation, the weight of the birds, and the volume ( weight andnumber) of food given to them were recorded almost every day.
RESULTS
1. Species and number of oiled seabirds

Fig. 1. Daily change in the number of seabirds rescued ( live) and collected (dead).
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A total of three birds of Kittiwake Larus tridactylus, Ancient Murrelet Synthliboramphus
antiquus and Red-necked Grebe Podiceps grisegena was first rescued on 9 January. The
number of retrieved birds increased, reaching the maximum ( 20 birds) on 15 January. The
number decreased once, but increased again. From 3 February, three birds at most weredaily found (Fig. 1). One bird of Black-tailed Gull Larus crassirostris was finally rescued

Fig. 2. Change in the species composition of seabirds rescued and collected.
on 10 March. Red-necked Grebes and Ancient Murrelets predominated during the first 5
day-period, followed by Hornbilled Puffins Cerorhinca monocerata and Pacific Gavia pacifica
or Black-throated Divers G. arctica 10 days later and Black-tailed Gulls 20 days later ( Fig.
Table 1. Species and number of the oiled seabirds rescued and collected in Fukui.
Order
Gaviiformes

FamilyGaviiae

Podicipediformes

Podicipedidae

Plecaniformes

Phalacrocoracidae

Anseriformes

AnatidaeCharadriiformes

Laridae

AlcidaeUnknown
5 orders

4 families

Species
Red-throated Diver
Pacific DiverBlack-throated Diver
Red-necked grebe
Black-necked Grebe
Japanese CormorantPelagic Cormorant
European Pochard
Harlequin Duck
Red-breasted Merganser
Herring Gull
Slaty-backed Gull
Common Gull
Black-tailed Gull
Kittiwake
Common Guillemot
Ancient Murrelet
Least AukletHornbilled Puffin
19 species

Alive
Scientific name(birds)Gavia stellata
1
Gavia pacifica
5Gavia arctica
11
Podiceps grisegena
14
Podiceps nigricollis
2Phalacrocorax filamentosus
2
Phalacrocorax pelagicus
0
Aytthya ferina
0Histrionicus histrionicus
0
Mergus serrator
1
Larus argentatus
1
Larus schistisagus
0
Larus canus
1
Larus crassirostris
17
Larus tridactylus
1
Uria aalge
0Synthliboramphus antiquus
14
Aethia pusilla
1
Cerorhinca monocerata
10Total(birds)
72
Ratio(%)
42.4

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Dead
(birds)
0
6
2
7
2
4
2
1
1
0
1
2
0
3
1
1
11
1
52
1
98
57.6

Subtotal(birds)
1
11
13
21
4
6
2
1
1
1
2
2
1
20
2
1
25
2
53
1
170
100.0

Ratio
(%)
0.6
6.5
7.6
12.4
2.4
3.5
1.2
0.6
0.6
0.6
1.2
1.2
0.6
11.8
1.2
0.6
14.7
1.2
31.2
0.6
100.0

2) .
A total of 170 birds consisting of 19 species ( six families of five orders) was found oiled
along the seashore of Fukui Pref.: 72 live birds ( 42.4%) and 98 dead birds (57.6%). The
majority of oiled birds was occupied by oceanic seabirds of Hornbilled Puffins (31.2% ) ,Ancient Murrelets (14.7%), Pacific and Black-throated Divers ( 14.1% in total) and Rednecked Grebes (12.4%), which totally covered 86.4% of all the oiled birds ( Table 1).
The average mortality of each species was 54.1 ± 36.3(SD)% (n=19 species). The patrol
proved the mortality of Hornbilled Puffins was the highest ( 98.1%) (Table 1).
Oiled birds were found in a total of 12 municipalities in Fukui Pref., mainly in Awara
Town (27.1%), Mikuni Town (22.4%) and Fukui City (15.9%) (Fig. 3).

Fig.
unicipality where oiled seabirds were rescued and collected in Fukui.

3. M

2. Rehabilitation and change in the body weight of birds
A total of 72 birds ( 42.4% of all birds) of 14 species was rescued, of which 65 birds
were medically treated and rehabilitated. The birds were cared for every day as follows:
1. Checking the remaining food set on the previous day
2. Checking the health condition and weighing the body
3. Feeding and medical prescription
4. Self bathing or cleaning
5. Self preening or drying
6. Keeping warmth (in winter)
The treatments of 3 to 6 were repeated if necessary.
Most of the birds were unable to intake water or food due to dehydration, oil pollution
and stress of cleaning, so they were fed by hand with a mixture of minced fish, vitamins,
glucose and so on. A few days later, the birds accepted fish themselves, mainly Hypomesus-4-Fig. 4. Daily change in the body weight of seabirds after cleaning ( continued).

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Fig. 4. Daily change in the body weight of seabirds after cleaning ( continued).

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Fig. 4. Daily change in the body weight of seabirds after cleaning ( continued).

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Fig. 4. Daily change in the body weight of seabirds after cleaning ( continued).
nipponensis(pond smelts) and Engraulis japonicus, sometimes Sardinops melanostictus .
Birds were fed sufficiently every day. The birds recovered their loss of body weight withinseveral days (Fig. 4).
There was a tendency that birds losing their body weight again ended
in death. The weight (y g) of fish given for food was correlated with the body weight(x g) of the birds (Fig. 5) as follows:
y=23.4+0.28x (r=0.94, P<0.001, n=27)
The average weight of a pond smelt was 7 g. The number (y fish) of fish given to birds-8-Fig. 5. Correlation of the volume ( a) and number (b) of fish given to the body weightof the seabirds.
Table 2. Means (± SD) of the body weight of seabirds, the volume and number of pond
smelts given to birds.
Species
Gavia pacifica
Gavia arctica
Podiceps grisegena
Podiceps nigricollis
Phalacrocorax filamentosus
Mergus serrator
Larus crassirostris
Synthliboramphus antiquus

Body weightof bird (g)1,629 ± 114
2,189 ± 422
810 ± 106260 ± 281,969
657
462 ± 46
166 ± 15

Volume offish (g)539 ± 131580 ± 185
243 ± 4261 ± 19757
191
129 ± 46
107 ± 21

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Number of fish
(pond smelt)
77 ± 1983 ± 26
35 ± 69± 3
1082718 ± 715 ± 3n(birds)
3
4
5
2
1
1
6
5

was correlated with the body weight ( x g) of birds significantly ( Fig. 5) as follows:
y=3.3+0.04x (r=0.94, P<0.001, n=27)
Birds of each species were fed with a food volume of 26.5 〜 64.5% of their body weight(Table 2).
A total of 34 birds (20.0% of all birds) was transported to the releasing site after amean of 11.7 ± 11.3(SD) days (range=1-37 days, n=34 birds) . Birds which were physicallyhandicapped during the rehabilitation died in a mean of 13.8 ± 36.2(SD) days (range=0-160
days, n=31 birds).
DISCUSSION
1. High mortality of oiled birds
Oil pollution extended over a total of 12 prefectures as a result of the accident of the
Nakhodka. A total of 1,315 birds was retrieved from polluted areas ( Japan Environment
Agency, pers. comm.), of which a total of 170 birds ( 12.9%) was found in Fukui Pref.
Of those 170 birds, 98 birds ( 57.6%) were collected as casualties. The high mortality
seemed to be caused by bad weather conditions ( high waves, coldness in winter) .
Cleaning and rehabilitation recovered a total of 34 birds ( 20.0%) in Fukui, which was
47.2% of the rescued birds and 20.0% of all the birds. The low recovery rate was mainly
due to insufficient facilities and to the lack of experts for seabird rescue. Furthermore, thehospitals for medical treatment and the center for rehabilitation were very far from theseacoast. It took a long time to transport the oiled or weakened birds, so resulted in highmortality of the birds.
It is difficult to provide a seabird rehabilitation center in every prefecture. It is realizablefor the Environment Agency to have the center in Tokyo and to arrange the transportation
system. Municipalities should prepare preliminary facilities and volunteers ( veterinarian,keeper and ecologist) for rescuing wildlife.
2. Rehabilitation
It is necessary to rehabilitate seabirds paying attention to the points below.
1. Species identification and habit of birds
2. Size of cage and pool
3. Air- and water-conditioning
4. Lighting
The species of oiled birds were identified, which gave us the information of their habitatand habits. Most of the seabirds have a specific food diet and feeding behaviour ( Nelson1980). The birds were given several species of fish as food. Of them, Pond smelts werethe most suitable: Birds swallowed the fish easily because the pond smelts have a long,
slender and compact body. Some species foraged the fish in the pools better thanin the boxes.
It was difficult for seabirds to walk on the ground because their legs were attached at the- 10 -

rear of the body. This sometimes developed into injury and arthritis in the legs. Eachbird was kept separately in the small wooden boxes (60cm(l)× 60cm(w)× 90cm(h)) with a net
bottom, which restricted the mobility of the birds. However, the legs are apt to get dry,so we need to wet them with water. It is better for swimming pools to be wide and deep
because the birds can relieve and bathe themselves, which reduces stress. If available, thepools should be filled with salt water; Fresh water might make seabirds sensitive to disease.
The room for keeping birds should be kept warm ( ca. 25 ℃) and the air well circulated.
The swimming birds got saturated in about ten minutes because the birds cleaned feathers could
not repel the water. Such birds need to be cleaned again. It was necessary to dry out thefeathers and down soon after bathing and swimming. Furthermore, high powered light helps
to induce self preening.
Once the birds were injured or weakened in their legs, they could not get well, resulting
in death. It was most important for us to recover birds for releasing as soon as possible.
ACKNOWLEDGEMENT
I am grateful to the staff of the municipalities, the members of the Wild Bird society and thevolunteers who rescued and rehabilitated birds oiled in the accident. Also to Ms. Claire
Meacock who read this manuscript and corrected my English.
SUMMARY
The Nakhodka, a Russian tanker, sank with C-type heavy fuel oil in the Sea of Japan, off
the shore of Shimane Pref. on 2 January, 1997. The oil reached the coasts of Fukui Pref.
between 7 and about 27 in January. A total of 170 birds, 19 species ( six families offive orders) was found oiled along the seashore from 9 January to 10 March: 72 live birds(42.4%) and 98 dead birds (57.6%). The majority of the oiled birds was oceanic seabirds,
Hornbilled Puffins (31.2%), Ancient Murrelets (14.7%), Pacific and Black-throated Divers(14.1% in total) and Red-necked Grebes ( 12.4%), which totalled 86.4% of all birds.
The average mortality of each species was 54.1%, of which the rate of Hornbilled Puffins was
the highest (98.1%). The weight and number of fish given were correlated with the bodyweight of the rehabilitated birds accordingly. Birds of each species were fed with a foodvolume of 26.5 〜 64.5% of their body weight. A total of 34 birds (20.0% of all the birds)
was transported to the releasing site after a mean of 11.7 days. Birds which were physicallyhandicapped died in a mean of 13.8 days during the rehabilitation. The high mortality ofthe oiled birds seemed to be due to the bad weather conditions, insufficient facilities and alack of experts for bird rescue in the area.
LITERATURE CITED- 11 -

Day, R.H., Murphy S.M., Wiens, J.A., Hayward, G.D., Harner, E.J. and Smith, L.N.. 1995.
Use of oil-affected habitats by birds after the Exxon Valdez oil spill. ASTM special
technical publication 1219:726-761.
Evans, M.I., Symens, P. and Pilcher, C.W.T.. 1993. Short-term damage to coastal bird
populations in Saudi Arabia and Kuwait following the 1991 Gulf War marine pollution.
Marine Pollution Bulletin 27:157-161.
Jackson, S.. 1993. The effects of oil pollution on seabirds. Penguin Conservation 6( 3 ): 4-9.
Nelson, B.. 1980. Seabirds, their biology and ecology. 224pp. Hamlyn, London.
Ohata, J.. 1988. Injury to seabirds by the illegal dumping of waste oil in the Japan Sea off thecoast of Shimane prefecture. ( In Japanese with English summary.) Strix 7:299-300.
Ohata, K., Nemoto, S. and Murai, M.. 1993. Mortality of seabirds due to oil contamination
along the Tomakomai coast, Hokkaido. ( In Japanese with English summary.) Strix 12:
214-218.
Piatt,J.F., Lensink, C.J., Butler, W., Kendziorek, M. and Nysewander, D. R.. 1990. Immediate
impact of the 'Exxon Valdez' oil spill on marine species. Auk 107( 2 ): 387-397.
Symens, P. and Al Salamah M.I.. 1993. The impact of the Gulf War oil spills on wetlands
and waterfowl in the Arabian Gulf. IWEB special publication 25:24-28.
Wiens, J.A., Crist, T.O., Day, R.H., Murphy, S.M. and Hayward, G.D.. 1996. Effects of the
Exxon Valdez oil spill on marine bird communities in Prince William Sound, Alaska.
Ecological applications 6(3): 828-841.
福井県におけるナホトカ号沈没事故による重油汚染を受けた海鳥類の種とリハビリテーション
大迫義人１
ロシア船籍のタンカー，ナホトカ号が，1997 年 1 月 2 日に島根県沖の日本海で C 重油を積んだまま沈没した．船から流れ出た油が，1 月 8 日から 27 日頃にかけて福井県に漂着し，この事故で，1 月 9 日から 3 月 10 日までに，5 目 6 科 19 種 170 羽（72 羽の生体と 98 羽の死体）の海
鳥が保護または回収された．その多くは，海洋性の鳥類であるウトウ（31.2%），ウミス
ズメ（14.7%），シロエリオオハムまたはオオハム（14.1% ）とアカエリカイツブリ（12.4%）であった．死体で回収された個体数の割合は，種あたり平均 54.1% で，中でもウトウの死亡率は 98.1%と最も高かった．リハビリテーションで与えた餌の魚類の重量と尾数は，鳥類の体重と有意な正の相関があった．また，餌の重量は鳥類の体重の 26.5 〜 64.5%に相当した．全体の 20.0%にあたる 34 羽の鳥類が，保護されてから平均 11.7 日後に放鳥された．
リハビリテーションの間に負傷した鳥類は，平均 13.8 日で死亡した．保護・回収およびリ
ハビリテーションの時の高い死亡率は，事故時の悪天候および海鳥類救護の施設の不備と専門家の不足によるものと考えられる．
1.福井県自然保護センター．〒 912-0131 福井県大野市南六呂師 169-11-2- 12 -