A high degree of effort, expressed in terms of total man-hours, was expended for all whale shark hunting operations, particularly those using gaff hooks (Table 6).
The average fishing effort of fishers using gaff hooks was about 316 man-hours in Pamilacan and 115.2 man-hours in Guiwanon.
When using hand spears, the Pamilacan hunters again spent more fishing effort than the Guiwanon hunters. For one respondant in Pamilacan, fishing effort was calculated at 144 man-hours compared with an average fishing effort for hand spearing by Guiwanon hunters of 83 man-hours.
Average fishing efforts for Balite and Manuyog hand spear users were calculated at 61.6 man-hours and 23.3 man-hours, respectively. Pamilacan hunters spent more time travelling to the fishing grounds than Mindanao hunters.
The volume of landed catch was highest in Pamilacan compared with either Guiwanon or Camiguin (Table 7).
The average volume landed per trip by Pamilacan hunters was reported at 2.47t (gaff hook) and 6.5t (spear).
Guiwanon reported only 2t for gaff hook and 3.9t for hand spear. Balite and Manuyog reported hand spear catches of 4.4 and l0t, respectively. Both gaff hooks and hand spears in most sites (except for hand spears in Pamilacan) were used not only for whale sharks but for other species as well, such as mantas, devilfishes, other sharks, and even dolphins and whales.
Income per unit effort (IPUE) of hunters follows trends observed in landed catch, particularly on a per trip basis (Table 7). Assuming the income was shared equally among crew members regardless of status, Pamilacan gaff hook users had a higher income than Guiwanon hunters.
On a per man-hour basis, spear hunters at both Pamilacan and Guiwanon earned more than gaff hook users. Sharing strategies varied between fisheries. Typically, most of the catch and income went to the owner of the boat and the head hunter. Local capitalists and/or brokers who lent the hunters money for operations received the highest income since they have the right to the catch.
Table 6. Fishing effort (manpower x fishing hours) of selected geartypes used in the five primary whale shark
ray fishery sites
Local name
, based on interviews conducted in February-March 1997.
N Cetaceans; F = fishes in general; FH = number of fishing hours per trip; 1 Mobula: MP = manpower or number of fishers; R =
at a time).
rays in general; S = sharks in general; WS
Fishing hours
= invertebrates; N= number of respondents; M = Manta and
= whale sharks. (Note: fishers may have more than one gear
Table 7. Catch per unit effort (CPUE) and income per unit primary whale shark/manta fishery, based on
Gear type
Avg. = average of fishers; R = interviews conducted in F
CPUE
= fishes in general; I = invertebrates; N= number of respondents; M
of selected geartypes ebruary-March 1997.
Avg. IPUE (PhP) per mnhr
used in five
per mnhr
= Manta and Mobula; MP = manpower or number sharks in general; WS = whale sharks; mnhr = man hours. (Note: fishers may have more than one gear at a time).
Table 9. Summary of whale sharks landed in various fishery sites in Visayas and Mindanao for the 1997 season, based on on-site enumeration and reports from cooperators in this study (Note:
Camiguin are not available.)
No.
Fishery sites
1. Pamilacan I, Baclayon (Bohol)
2. Guiwanon, Talisayan (Misamis Oriental) 3. Tagdodo, Mati (Davao Oriental) 4. Mantigue I., Mahinog (Camiguin) 5. Usocan, Plaridel (Misamis Occidental)
data from 6. Katipa, Lopez-Jaena (Misamis Occidental)
7. La libertad (Misamis Oriental) 8. Kinoguitan (Misamis Oriental) 9. Amlan, Negros Oriental 10. Buyuan, Tigbauan (Panay) 11. Samal I., Davao
Total
The highest income per man-hour went to Manuyog hand spear users, who also had the shortest time per trip.
Comparative whale shark catch data 1990-1997 in four of the primary fishery sites, based on fishers' memory, published information and on-site recording, are given in Table 8. Surprisingly, the more efficient Pamilacan hunters reported a smaller number of whale shark landings compared with Guiwanon hunters. Between 1993 and 1996 Pamilacan hunters caught an average of 30 individuals per year, whilst Guiwanon hunters caught about 96 individuals per year. Together the two sites landed 598 whale sharks 1993-1996.
From on-site monitoring in Pamilacan and Guiwanon alone, a total of 106 whale sharks were landed in 1997 (Tables 8 and 9), about 29% lower than the yearly average for the two sites in previous years. In nine fishery sites, at least 140 whale sharks were landed for the 1997 season (Table 9). The average number of whale sharks landed per site, therefore, is about 16 individuals, some 27% lower than the average yearly catch in two sites alone for the past four years. This clearly suggests that there is a decline in the number of whale sharks taken, despite an increase in the number of fishery sites.
Comparing the 1993 and 1997 catch data there was a sharp decline in the CPUE values, expressed in terms of the number of whale sharks taken per boat (Table 10).
Fishers' memory of the historical catch of mantas and/
ordevilfishes was sketchy (Table 11.) Fishers had problems segregating catches into species, often confusing mantas and devilfishes. Most often, catches were underestimated.
Fishers feared that the Bureau of Internal Revenues would investigate them if they reported higher catches. During Table 10. Comparative estimates of 1993 and 1997
whale shark catch per unit (or CPUE, expressed in number of whale shark taken/boat) in two fishery sites - Pamilacan (PAM) and Guiwanon (GUI).
1993 Season 1997 Season (Alava et a/. 1997) (this study)
PAM GUI PAM GUI Catch
(No. of whalesharks) 80 100 68 38 Unit effort: no. of boats 18 10 40 10 CPUE estimates 4.44 10 1.7 3.8
CPUE= catch/unit effort
Table 8. Comparative data on interviews conducted (June 1993C; 1997d).
ind = individual
35b
1990-1997 whale shark catches in four of the primary fishery sites, based on 1996a; February-March 1997b) and actual on-site enumeration (April-May
Guiwanon Balite Manuyog
No. ind. L (min-max, m) No. ind. L (min-max, m) No. ind. L (min-max, m) Total (20-30/yr 2.5-7b prior to 1997b)
Table 11. Fishers'
recall on historical catch of in four fishery sites.
Estimated
the 1995-1996 season in Bohol, the fishers reported landing about 1,000 individuals (WWF-Philippine Programme 1996). In 1997, the estimate was 50. Despite such limitations, the reported values show higher landings in the 1960s than in later years. Though actual catch data for mantas were not available for this paper, the total number of mantas landed is probably much higher than the number of whale sharks in a season.
Whale shark and manta ray fisheries, therefore, are viable, judging by the increasing number of fishing villages, people and boats, involved. Conversely, declining catch rates for both the whale shark and manta ray indicate that