20100702雨傘旗魚標識放流

Sailfish tagging cruise_Matthew finding sailfish

離上回搭鏢船出港的時間已經相距近五個月
因為三月後，就是鬼頭刀與雨傘旗魚的季節
大部份的鏢手就改以 「放緄」(延繩釣)為主
當然，如果有發現旗魚，仍然會順便給他鏢上來

七月二日，清晨三點半就起床
三點四十到公司集合，四點到港口集合

登船的第一件事，江博士與船長在處理衛星標與鏢竿

#2

時間近五點，今天的雲多了些
手持快門1/4秒、光圈F4、ISO 400

有 好一段時間沒有看日出了
太陽露臉前，天空又藍又橘，仔細看還可見V字型的光線

#3

時間五點零三

圖 左處可見三仙台，日出前光線變化很快
每一秒幾乎都有不一樣的感覺

#4

時間五點二十八分

氣象預報今日為西南風，所以出港的船並不多
加上最近實在真的有夠熱，也晒出了一身疲憊

#5

特別來賓為澳籍的馬修
馬修第一次登「龍漁發」，一整個精力旺盛，而且還是凌晨三點從東河趕來
馬修：「第一次看到鳥，第二次看到海豚，第三次終於看到旗魚」

#6

夏天的浪沒什麼起伏

#7

時間七點三十六分
天空的雲多了些，但也阻擋不了台東的烈日

#8

從四點多出港，一路晃到九點多都不見旗魚
其間也僅捕獲二尾不足三公斤的鬼頭刀

船長說：「先吃中餐好了…」

早上九點多就準備起了中餐
吃的就是新鮮鬼頭刀所煮成的魚麵

上圖，早上九點五十三分，風變了，從南風轉為北風
船長發現了旗魚，但沒一回兒，魚跡不見了

#9

下午一點十七分
再次發現旗魚，如果我不圈出魚的位置，應該很難看的出來吧

#10

破雨傘鏢射較不容易，因為体重很少超過100公斤
而且，大部份捕獲幾乎都 在50公斤以下
目標物小，所以技術上比鏢射白肉旗魚難

#11

其實在近十二點時，船長成功標識了一尾雨傘旗魚


雨傘旗魚（Istiophorus platypterus）
台灣俗稱破雨傘(phóa-hō-soàn)，大陸名為平鰭旗魚，英名Sailfish，第一背
鰭高度遠高過體 高。

錄影：陳信志、Matthew
攝影：江偉全、洪曉敏
剪輯：洪曉敏

Ocean Field Operations _ July 2 2010

Tuna and Billfish Tagging Project

4.00am Onboard

Captain: Yung Fu

1^st Mate: Wiket

Project Leader: Riyar

Still Camera: James

Video 1: Shing zja

Video 2: Matthew

Objective – join with experienced harpoon fishermen to conduct harpooning PSAT on sailfish

Pre dawn departure required meeting at the office at 3.45am to collect camera and tagging gear. Riyar has prepared 2 X-tag PSATs from Microwave Telemetry.

The harpoon spear has been specially modified for the Tag attachment. Video footage was gathered for this process as the fork is sterilized using alcohol; the darts are placed on each point of the harpoon.

The tether for the tag is an 8 cm lead attached to 3.5 cm swivel then to two 14 cm leads for the dart’s which penetrates and secure under the fish skin by using a surgical grade nylon flopper taghead that resists extraction from the muscles. An even better method is to place the dart in the muscles at the base of a dorsal fin so that the barb penetrates the bony extensions at the base of the fin rays.

Application however is not so easy - as the day presents.

Leaving Shinkang harbor we travelled south for about 2 hours. The weather during the early morning was of a seemingly stable low. Humidity was high and not a lot of wind. These calm warm conditions made the prediction of finding sail fish slim. Other fishermen were already located 3 – 5 km offshore from the coastal town of Donghe. There was a tide rip apparent in the sea surface as the calm waters met small choppy waves. We then began a spiral of the immediate area in communication with the long line boats that where fishing there.

We received a reported sighting from a nearby vessel and went to the vicinity with no affirmation. Reference to the weather made the morning seem long and unproductive. An 11 o’clock knock off time was proposed.

Fortunately mid morning the desired change came through, the wind shifted form a southerly to an easterly and then a north east. This brought cooler temperatures and a higher cloud cover, altocumulus. The waves increased and came from the north. We had reached our southern most point and where headed slowly north returning to Cheng gong harbor.

Our morning had not been totally unsuccessful. Towing trolling lines had captured two dolphinfish which Wicket began cooking for lunch. The preparation was interrupted with a possible sighting and need for the Wicket to grab the harpoon on the platform at the bow of the boat. The harpoon boat is a conventional v hull with a plank or platform extending over the bow from which the harpooner has direct access to the fish beneath him. The harpoon consists of a 15 – 18 ft pole fitted with a stainless steel trident.

Lunch was resumed when the immediate search suspended and greatly appreciated and quickly devoured by the team. The changed weather, a few attempts in which expectation had grown meant staying past the 11 am deadline, 12. 30 pm was declared.

A few more unfulfilled sightings were made, the learning experience of what to look for, the challenge of then filming activity, the recognition that the wide horizon, the blue depths and the rocking of the boat was easing towards rest when a fin had been seen.

Captain Yung Fu powdered the boat onto the fishes presumed course.

Thankfully the sighting resulted in a tagging event. The fish is difficult to see yet the harpoon plunged into the sailfish anterior alongside the dorsal fin. Because of the bent fork it is hope that at least one of the darts secured itself. The timing of the harpoon requires experience, a bait fish is thrown into the water directly in front of the vessel as prey for the sailfish. As the sailfish surfaces to grasp the bait the harpooner thrusts his spear into the fish. As demanding as a coordinated strike entails avoidance of fatally injuring the fish is part of the harpooner skill.

Location, time and tag number are all recorded for data to be correlated into the fishes recovery and migratory paths.

This information is expected to provide insight into the stock size, migration, spawning as well as daily habitats such as depth of dives and surface feeding.

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