Table 1.

Sightings and numbers of gray whales recorded on- and off-transect during aerial surveys off northeast Sakhalin Island, 31 July–19 November 2001

Survey period	Piltun			Offshore			Extensive			Lunskoye			Total
	km	On	Off	km	On	Off	km	On	Off	km	On	Off	km	On	Off
31 July–02 Augustb	0a	69/79	7/12	0	NS	NS	0	NS	NS	0	NS	NS	0a	69/79	7/12
02–10 Augustc	0a	127/142	23/31	0	NS	NS	0a	0/0	0/0	0	NS	NS	0a	127/142	23/31
11–16 August	951a	177/245	68/87	0a	1/1	0/0	0	NS	NS	0	NS	NS	951a	178/246	68/87
17–21 August	618a	77/98	10/12	0	NS	NS	0	NS	NS	0	NS	NS	618a	77/98	10/12
22–31 August	1251a	111/145	31/41	0	NS	NS	117.8a	11/16	0/0	0	NS	NS	1369a	122/161	31/41
1–8 September	2943	104/132	26/33	0	NS	NS	522.2	0/0	0/0	0	NS	NS	3465	104/132	26/33
9–20 September	1563a	62/76	16/28	1351.7a	67/82	18/20	639.3a	3/4	0/0	0	NS	NS	3554a	132/162	34/48
21–30 September	361a	44/52	5/7	353.9a	50/65	12/18	365.1	1/1	1/1	0	NS	NS	1080a	95/118	18/26
1–10 October	578	18/24	1/1	764.46	34/48	7/9	703.7	4/6	1/1	0	NS	NS	2047	56/78	9/11
11–26 October	178a	22/25	0/0	612.33a	54/69	9/16	0	0/0	0/0	0	NS	NS	790a	76/94	9/16
15–19 November	540	18/23	7/9	972.93	4/7	1/1	662.2	0/0	0/0	0	NS	NS	2175	22/30	8/10
Total	8982	829/1041	194/261	4055	210/272	47/64	3010	19/27	2/2	0			16048	1058/1340	243/327

NS Not surveyed

^a Some or all GPS data were missing, therefore, calculated survey effort (km² ) is under represented.

^b Including morning survey on 2 August

^c Including afternoon survey on 2 August