THE MINI SEINER FLEET OF THE NORTH JAVA COAST : A Case Study of Their Fishing Activities

Fishing effort is often a difficult parameter to identify in halieutic st,udies and even more so ifthe study involves coastal and artisanal frshing spread along a coast more than 1,000 km long. This is the case of the study of the mini seiner fleet operacing in the Java Sea. In order to estimate this descriptive parameter of the fishing effort, it has been suggested to use the method of calculating the average activity rate and at Che expense of given on certain hypotheses, to translate these rates into estimates of the number of fishing trips. This article offers a first global approach of the mini seiner fleet operating in the Java Sea from ports located on the north coast of the island of Java. It is thus demonstrated that this fleet's operating activities although more or less significant, were unintenupted all through the year 1995, the landmnrk year for this study. This study also described the first reason for the heterogeneity of the fleet from the dynamics of utilization of the landing ports by mini seiner fishing units.


IIvTNODUCTION
From the definition by Poinsard and Le Guen  (1975) adapted by Laurec and Le Guen (1g81), the fishing effort applied to a stock of aquatic animals is a measure of all the different methods used to catch this stock by the fisherman during a specific time interual.This definition implies that one must take into consideration the number of vessels and their characteristics, the fishing gears used, the level of activity and the human capacities in play, etc (Lauree & Le Guen, lgSl).
According to these authors, the fishing effort therefore corresponds to a quantifieation of the fishing activity in a time interval that relates to the exploitation of one stock or unit of manage- ment (Laurec & Le Guen, 1981) taking into consideration isolation and homogeneity hypo- theses.
For artisanal or coastal fishing, the study of the fishing effort is complicated by the hetero- geneous nature of this fishing effort, by the difficulty of setting standards in order to integrate the different fleets of artisanal fishery and by the relationship of this activity between different target species and a sharing of the stocks between artisanal and industrial fisheries (Charles-  f)ominique, 1991).The study of the fishing activity conducted on the whole of the artisanal fishery, or on a stratum there of, aimed at understanding the importance of the activity deployed either by a global approach of all the fishing units, or on an individual basis by fishing unit or group of fishing units.
By using this approach, the entire artisanal fishery can be characterized by the potential fishing units in activity, by an average number of trips by unit, by the number of days in activity and by the average or individual length of fishing units.It is also possible to establish a diagram that describes the activity by days workecl and idle days and possibly explaining the reasons of inactivity of both short and long duration.
The estimated parameters are indicators of the dynamics of each of the different areas of artisanal fishery.They allow the geographic ancl tempnral variations of these areas to be identified and to estimate their evolutionary capacities.ln the Java Sea, the mini seiner fleet can be compared to a fleet of artisanal fishery: the numerical potential is greater than l,l]00 units (Potier & Sadhotomo, 1995); the number of landing points is significant, more than 80 @coutin et al,, 1997); the possibility of rapidly changing the landing site introduces a major difficulty in following individual fishing units (Flariati etaI., 1995); the presenee among this fleet ofvessels in a variety ofshapes describes a notion of heterogenity and the possibility of partitioning IRD-HEA, BP 5045, 34032 Montpellier Cedex 1, France Researcher ofthe Research Institute for Marine Fisheries.Jakarta 108'

Figure I
this fleet into more homogeneous subgroups (Wiiopriontt e.t al., 1996; Ecoutin et al., 1997).ln order to estimate the fishing effort by mini seiners operating in the different areas of the north shore of the Island of Java (Figure 1), by studying their activities, a regular sunrey of a sample of fishing units would have been necessary.Because of the significant number of the fleet and a lack of time to complete the study, only a global approach could be accomplished' Nevertheless.by this global approaeh, it is possible to define certain descriptive parameters useful for a first approach to the fishing activity such as the number of active days during a year.explanations for the main fishing idleness and information on the spatiotemporal variability of the distribution of this activitv.This is not sufficient to translate the results obtained by the units of this fleet into an estimate of the total catch.but it does allow the completion of certain hypotheses to estimate a conversion factor of the results into total catches.110' 112" 114' 11   The Java Sea and its surroundings

Presentation of the Ports of the Study
Daily listings of landings by mini seiners were used to complete the study.During l99Fr, these listings were recorded in eight importantports on the north shore of Java (Figure 2).Different censuses of the mini seiner fleet operating in the Java Sea (Ecoutin e.t al., 1997; Jung, 1998) were used to make this choice.The sampling plan included a ninth location.the port of Brontlong located in the province of East Java @iguro' 2' no' tl).This port was the subject of a specific monograph (i,r-,ong,-1997) ancl its results could not be taken into account for this work.
From West to East, these entries were recorded in: * Eretan Wetan (Figure 2, no.1), the only port of the study located in the province of West Java' is a Ianding and commercial destination for fish from fleets using different fishing techniques: qillnets, Danish seines, mini seines' ln 1994'    IFR Journal VoL V !1o. 1. 1999   111" 113"

Portno.T-Bulu
Poftno.8-ISrondong Portno.9-Krarrji The I'ishing units from the villages located between Rembang and Sarang regularly visit, this port.Mini seiners dock at, the end of a long pier built, on a bezrch where the water level is verv low.
* Tasik Agung (no.5) is one of the auction places of the village of Rembans.This TPI is diff'erent in that it trarles pelagic fish czrught mainly by mini seiner units and secondly by large anrl medium seiners (57   * Kranji (no.9) is a small TPI located in the east of Brondong port, where fishing units using m4ny artisanal fishing techniques land (Luong,   1997).

Presentation of the Surveys
Each sale of a fraction of a fish load made by the mini seiner fishing units was recorded by the administration of the TPI in a book called buftu bakuL The different listings were then grouped by fishing unit and recorded on specific sheets for this study.The type of data collected on these pages was information needed to identify the fishing unit (name of the boat, name of the owner, the captain.origin of the fishing unit), information on the fishing trip (fishing location, duration, possible use of fishing aggregating device) in addition to contents of the catch by category of species.Usually, 6 and 8 categories of species were written up.This content was valued by weight and often by economic value.
Comparison between the lists of fishing units on these study sheets anad the data in the buhu bakut (description by unit sale, daily sales for each unit that landed) showed that there were no differences in the numbers of mini seiners that arrived each day.The information recorded by each TPI was therefore correctly carried forward in the data acquisition chain of this study.

Unit of observation
The landing yielded in one fishing unit of a fishing trip as the basic element in the analysis of fishing activity, represented the unit of observation.Because the unit of observation chosen was the landing of catches recorded by the TPI and also as an indicator of a fishing trip, there existed some bias for the fishing trips whose landings were not recorded by the TPI: catches of small quantity, direct sales to a preferred buyer.
In addition, the choice of this unit of observation, which was based on a fishing trip, did not allow the extrapolation of the fishing activity of mini seiners into number of days at sea.This latter parameter was often considered a more precise indicator of the level of fishing activity.Depending on the landing location and the fishing seasons, the duration of a trip to sea could vary from a few hours to il or 4 days.[n a few cases, the Iength of a trip could be even greater; this was the case of mini seiner units that sold their cdtch directly at sea to specific ships, the gendang boat (Luong, 1998).These gendnn'g boats sold later the catches on Brondong harbour (Luong, 1997).
In 1995, more than 25,500 entries were recorded in the eight villages described above.TWo of them were not taken into consideration in this study of fishing activity.One was the TPI in Batang (no.ll in Figure 2) where the data were not validated and the other was the village of Bulu (no. 7, Figure 2) where the data for the year 1995 were too incomplete to be able to conduct this type of analysis.

RESULTS AND DICUSSIONS
Global Analysis of the ActivitY Of the remaining six villages in the sample (one in West Java, four in Central Java and one in East Java) and after validating the inquiries (approximately O.\o/oof the inquiries were invali' dated), the sample contained more than 20,100 entries spread unevenly over the 12 months of the year (fable 1).

Analysis of the ActivitY Calendar
The number of inquiries (entries) recorded each day varied from 0 (value observed l1 times during the year or i3%) to 160 inquiries (obser' vation of March 29'h, 1995).The average number of daily entries recorded was 55 with a standard deviation of 35.The histogram of the distribution of the number of daily entries did not show any specific shape to the distribution of the values between l5 and 90 entries per observation day (Figure ll).
A little more than l0% of the observations corresponded to days with no or few entries Qess than i0landings recorded).They were defined as days or periods with low activity.[n the same manner, approximately 10% of the obsewations corresponded to days or periods with high activity with a maximum of entries recorded (more than 100 daily inquiries, Figure i)).

* Study of the periods with low activity
During 1995, four main periods of low activity were obsewed (fable 1, days circled by a thick tine)' These sequences were formed with a minimum of six consecutive days of reduced activity following the definition stated above.They are the period's: a) from January 12 to 18 with an average of il'6 landings per day, b) from February 7 to lll' 3 landings per day, c) from March I to 8, 1.5 daity tandings and 6 consecutive days without a single inquiry, and d) from December 6 to 11, tn which period we can add the 13, with a little less than 2.5 daily landings and three days with no entries' El Low daily activity tf Hish activity IFR Journol Vol.V No,1, 1999 these conditions would therefore not be favorable for catching fish.One other is that, in Indonesia each year, fishermen organize some traditional celebrations named pes ta laut (celebration of the sea).They last a week but the date of these celebrations are different between each village.
Of the remaining days of the year where the fishing activity seemed reduced, May l0 and I I correspond to the ld.ulAcllw holiday (Table 2).
The second and third periods correspond to important religious holidays (table 2): the begin- ning of fasting rlay Rarnadhan for the second period and the end of the fasting month and the Idul Fi,tri holiday ar rhe beginning of March.The two other periods can not be explained by religious or civil events.One of the explanations given by the fishermen related these periods of low activity to the full moon phases during the rainy season, 43  2. Relationship between the periods of low activity for the mini seiner fishing units 6 less than l1 entries; XX less than 6 entries; XXX no entries) and hypotheses.Finally, it must also be mentioned that except for July 16.there were no other days of low activity between the months of June and November.
* Study of the periods with strong activity During 1995, three main periods of high fishing activity were observed (slashed boxes in Table 1): from March 23 to the beginning of April, with l3 consecutive days, the second half of September with 8 non consecutive days, and the secbnd half of October also with 8 non consecutive days.There were no days of strong activity observed in January (maximum observed, 68 entries), February (92), July (97) and l)ecember (98).Afew days meeting the criteria for strong fishing activity were found on an isolated basis during the months of April, May and June and between August and November in addition to the periods mentioned above.

* The frshing activity
In 1995, the mini seiners operated all year long (only 3% of days with no landings) on a more or less regular basis.This annual calendar of the fishing activity could be broken down into different main periods.
The period between the beginning of December and March 20 corresponded to a period of low activity for mini seiner units.This low activity was explained by two main phenomenas the first explanation related tn Ramad,hanr., the Moslem fasting month during which the general activity of the country was reduced.In 19g5, this period was in February andMarch.This explanation was not a seasonal constant as the dates ofthis holiday change from year to year.The second explanation was of a seasonal nature, during the full moon phase and during the rainy sea,son, especially but also to unfavourable environmental conditions for fishing activity (wind, waves, swells, eurrents, desalinization of the coastal border ) lower catches.
In 1095, the period between mid.March and mid-April was a period of strong and constant activity.
From mid.April to the beginning of August, the activity varied greatly from days of big activity to low activity.The average number of landings was slightly greater than the number calculated during the rainy season.The fishermen justified this strong variability of their activity to local climatic conditions that could disturb the fishing activity (Allain, 1996).IFR Journal VoI.V No.1. 1999  The last period, from the beginning of August to the end of November, correspondecl to a period of very high activity.No days of rerlucecl activitv were observecl ancl the average numbnr of daily entries recorded was greater than 70.
Variability of the acti_vity due to the lunar cycle At first glance of Table 2, there were no obvious relationship between the days of weak activity and the full moon periods.However, compared to an average lunar cycle, these days were spread over most of the lunar days, but 60% of davs without much activity were grouped between the five days before and four days after the full moon.The remaining days corresponded to the lclul Fitri period, a holiday which always falls on a new m(nn phase. The days or lleriods with strong aetivitv usually occurred, on a lunar month cycle, between the 8th and l6'h day, therefore surrounding the new moon phase (79% of observations).No days of this kind were observed during the week surrounding a full moon.
From the result of two observations on daily trips which based on lunar day, it was founcl that the evolution of fishing curve activities had been inter-correlated with seasonal effect.The correlation could be seen from two phenomenas of day fishing activities, i.e.: the fishing activities on lunar moon which was eight to twenty five days, and around the full moon which was less than eight days. (Figure 4).These observations seemed to contradict to the appearance of an absence of lunar effect on the variation of the activity of mini seiners.However, temporal series greater than one year must be used to test this phenomenon and determine whether there exist, a real lunar effect affecting the behavior of fishermen, whether it was a elimatic event related to the lunar effect or whether the rainy season was considered a resting season.

Analysis by Landing Site
The analysis of the fishing activity of mini seiners by landing site is presented from West to East.

* Eretan Wetan
Eretan Wetan is a constant and regular landing site throughout the year since activities at this TPI were observed in 9il% of days during the year of 1995 (lable ;l).Approximately 70% of tlavs with no landings were.within the four periocls of weak activitv for mini seiners (2.1) and the remaining days were either before or after these same periods' Morc ltrt:t:iscly, t,he gcneral acl'ivil'y at' l'ho' aur:l,ion ilrrce in I!rettrn Wettrn' whal'ever the fishing teehniques used, was reduced during twtl lreriotls (January 15-24 and December 5-18) corresponding to two periods of inactivity observed for the mini ieiner fleet.This seemed to confirm that these two penocls were not favorable for coastal fishing activities.
The fishing units recorded at the auction place in Erettrn Wetan usecl diverse fishing teehniques: gillnets.Danish seines, mini seines' Although the maximum entries recorded for one day was close to 50, it seemed that this auction place saturated at 22-25 daily landings.All fleets inclutled' ln 1l)91'r.mini seiner units lanclecl at this port werre only t,wo t;hircls of the working days of the auction plrrce with ?ln average numbcr of daily lantlingsrf ;3.35 calculated for a periorl of 216 davs (fable;l) In Eretan Wetan, there were no days where a large number of mini seiners was seen landing: in general, there were less than ?daily landings (95% of observations).
The stuclv of the seasonal varitrtion of the number of entries highlighted two main periods: (1) on one hand, from May to October (75% ot ann.lal entries of mini seiners, Table i)) where the units lancled almost every day (84% of working days) with an average number of landings generally greater than the annual average (3'8i)   ,',tr*"tuotii,ns by rlay studied); and (2) from Dccember until March where the average number of lanclings rlecreased (1.83) with a small number of clocking (fable 'l).

* Pekalongan
During the vear of 1995, in Pekalongan' entries for mini seiner fishing units were recor<led less than one out ofevery 2 days (45%) for an annual averago o('a litt,le mtlre than l2 tlailv enl'ries (l'able 3) Oontrarily to the prececling port'' there *u, u u.ry large variability in the number of daily entries with a maximum observed of 56' One fifth of the days observecl registerecl more lhan 20 observations.The annual activity calendar clescribed twrl periods with strong landing activity of mrni seiner i,rrit.","purated by periods with very minimerl activity: (t) fto-IVlarch 20 to the end of June with activity of two out of every three days' antl an uu."ug" of 21 entries per worklng gavi and (2) betwe.enSeptember lb and the end of Oct'ober which having the strme activity rate as t'he previor,li; period but with an average nutnber tlf i,rtt,tlttg" ller working dav much lower' around I 1 or 12 entries.l3etween these l,wtt lleritlcls' t'he number rlf landings observecl in Pekalongan was very weak iio ,"tox of working days for-a-n average of approximately 5 entries per day)' More than 90% oi u"its that ianrl in Pekalongan originatetl from towns locatecl in the province of East Jnva' One particularity of f'ekalongan wtrs the almost complete absence of landings during the week that inclurlerl the full moon and perirxls rtf both high ancl low activity.Pekalongan was the onlv one of the six ports st'utliecl where the nr:tivit'y of fistrlng units mezrsured by their landings was <lirectly or inrliroctly relattltl t'o the lunar r:y<:le' As a landing site for mini seiners, f'ekalongan therefore showerl tr strong variability in terms o{ Table 3. Main rnformation on the activity observed at the ports under study (Ne; number of mini seiner entries; NJe, number of days with mini seiner landings recorded; Ne/Je, average number of entries b1, days with entries).
Month (1995)  Total I , I presence-absence of these unit,s and in terms of numerical signilicanr:e ol' their presence.This strong variabilitv are direct and indirectly explained.by activity cycles related to the lunar cvcle.

* Banyutowo
Th-e port of Banyutowo.also called Tayu, was a small landing site for fishing units using various techniques and making fishing trips very close to the coast.It was used by the fleet of mini seiners when these units rvere fishing in areas near this village.A large maiority of these fishing units were not from Tayu; in l9gb.60% of the entries recorded were fishing units coming from Pr.ndang_an, a village located close to'l.asikAgung (Figure 2) and almost 409/o from the village of Sarang (Figure 2).
In 1995.mini seiner units lancled their catches a little more than Z days out of 13 (except fbr the month of May that was not studied) and for each day recorded, approximately 4 units were observed arriving.Here, as in Eretan Wetan, although the activity seemed sustained all year long, the daily variation of the number of lurrdirrgs was weak: for 80% of days recorded less than b fishing units landing.For the period from August to November, the activity of these units at the port of Tayu seemed to be a little stronger both in terms of days present and the number of units landing.
No lunar effect seemed visible since the landings were observed both on full moon davs and days surrounding the lunar phase.

* Tasik Agung
In 1995, at Tasik Agung more than 9,100 entries of mini seiner landings were recorded during il29 working days (Table B).The percent- age of days with entries was greater than g0%.This auction place therefore had regular activity all year long.Nthough there was a few landings by large and medium size seiners (['otier et al., 1995), this TPI only records mini seiner landings.The fishine units that unloaded their catch here were not native of this location.ln 1995, 4l% of Iandings recorded were units from Pandangan (another TPI of Rembang), 48%ftom Kragan and 11% from Sarang.The average number of entries per working day was around 25 entries recorded (fable 3).The variation of this parameter was strong since the daily maximum observed in 1995 was 88 entries.
During 1995, it was possible to pinpoint two main operating periods for this TPI: (1) from December to the end of February (before the Ramad,han period), where the rate of working days was close to 80% and daily activity was clearly inferior to the annual average with approximately 15 entries per day; and (2) from mid-March (after IcIuI Fitri) to the end of November where activity was constant, almost 100%, and the monthly average number of sales recorded was close tcl or greater than the annual average.During the months of .Iune and July, there was a slight decrease in the average number of daily entries' In terms of activity, Tasik Agung, an auction place in the village of Rembang was similar to -Eretan Wetan with regular and sustained annual activity.However, this activity was limited to mini seiner units whereas Eretan Wetan also records catches by pluri'technical units.Another diffe- rence between these two ports was the variabilitv of specific landings by mini'seiners.The port located in the province of West Java (Eretan Wetan Port) had a low daily variabfity which was not observed in Tasik Agrrng' * Sarang Sarang, a TPI located on the eastern fringe of the province of (lentral Java (Figure 2, no6), showed an activity slightly greater than in Tasik Agrrng as there were 9ll% of works days in the y.u" isOf.[n average, during the year, a little iess than 22 mini seiner landings were recorded on active days of this auction place' Here' as in Tasik Agung, the daily variability was high between observations of only one landing (7 times during the vear) and T0landings on the same day' As with the previous location, there were two main activity periods: (1) the first semester, with sustained activity but always below 100% (from 80 to 96%), in which the average number of daily entries was always clearly inferior to the annual average, except, in March, after the end of the Lebaranr,holidays, where claily activity was greater than the annual average; and (2) the second semester with 100% of working days' where claily rate of entries were greater than the annutrl average.ln Sarans, more than half of the landings were originated from fishing units registered in Sarang, while 44% was from fishing unit registered in Kragan and 2Yo registered in Rembang' * Kranji Kranji is a location where fishing units using vario.rstechniques of landing, with a predominance of mini seiner units' They iepresentecl two thirds of the 1,428 entries recordecl in 1995 (amount calculated for the lleriod May-December).During that year, entries were *oit ott 247 days (6?%, Table l3) and mini seiners landed during three quarters of these working days.On clays with activity, an average rrf more than 5 mini seiners landed their catch trt this auction place.These units were mainly from Ifuanii or bordering villages.

CONCLUSIONS
The units from the mini seiner fleet operated all year long with a few short periods of inactivity generallv corresponcling to the beginning and the end of ih" Itt.lo.t"sianLebaron' periocl' This   general activity could be divided into an annual cycle with strong activity during July to November and reduced activity cluring the rainy season from December to March.The landing ports for the fleet of mini seiner units could be broken down intn four different operating methods used: (l) Eretan Wetan, Ranyutowo and to a lesser degree' I(ranii: where pluri'technical fishing units lanrl never represent large numbers of mini seiners' trncl thlse fishing units were generally migrant; (2)  Sartrng, Ifuanji: the lantlings were dominatecl by native fishing units.Mini seiner units from neighboring viilages were unloaded at these busy and sometime very busy ports; (3) Tasik Agung' a constant and busy port which was a special ctrse in that it was an auction place specialized in large' medium and mini seiner fishing units concen' trates mainly in the commercialization of small pelagic .p..i.t coming from other neighboring ports; uttit (+) Pekalongan, which did not fit into any of the above descriptions, since this port *"i.o*", mostly migrating fishing units and the variability of the landing activity of mini seiners was very strong cluring the month' In 1995, the mini seiner units landed their catches from the Java Sea during approximately 825 to llll0 days.This indicated a relatively high global activity rate for the fleet since there were more than 90% of working days during the year.Now this maximum duration of activity for the fleet, and its potential activity, must be translated into an average annual activity rate calculated by fishing unit.This future analysis will have to use the known information on the activity of the units by establishing activity calendars by fishing units and taking into consideration the peculiarities of each ports where the catches were landed.In effect, these peculiarities could determine the different exploitation dynamics by large groups of fishing units.

Table l .
General activity calendar of mini seiner fishing units Distribution of the number of daily entries number of boats land'